Best Satellite Messengers and Locator Beacons

The Explorer+ will keep you in touch wherever you take it.

How the heck do you communicate, effectively, from the wild? If you're looking to solve this mystifying problem, there are a variety of solutions, personal locator beacons and satellite messengers among them. We called around and read up on the most innovative options before buying the best and testing them for months. We've enlisted the help of Search and Rescue experts, wilderness gurus, and professional backcountry risk managers. Test procedures run the gamut, but mainly include extensive technological research and extensive use (as directed) in the field. Your choice in this category could have real consequences. That's why we'd steer you to our Editors' Choice, which does everything you want and need (for a hefty weight and dollar cost). More than with many other categories of equipment we review, we encourage you to read and shop carefully.

Read the full review below >

Test Results and Ratings

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Analysis and Award Winners

Review by:
Jediah Porter and Chris McNamara

Last Updated:
May 27, 2018

Updated May 2018
The technology and service options for personal locator beacons (PLBs) and satellite messengers continue to expand and refine. For this round of testing we check out the innovative GoTenna Mesh and straightforward Ocean Signal rescueME PLB1. Our IFMGA mountain guide and wilderness risk management consultant reviewer has used emergency communication devices for decades and consulted in the past for providers of emergency communication service and equipment. Herein you will find new perspective, updated assessment, comprehensive critique, and conclusions with more real-world savvy than ever before.

Best Overall Messenger

Garmin inReach Explorer+

Editors' Choice Award

at Amazon
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Weight: 7.5 oz | Battery life: 100 hours
Easy one-handed SOS operation
Awesome two-way messaging
Smartphone interface works well
Pairs automatically on startup
Expensive upfront cost
Largest of the devices we tested

The Garmin inReach Explorer+ is the best messaging device in our test group. It pairs with an app on your phone and can send and receive many different kinds of messages. From customized, individual text streams, to bulk, pre-programmed messages (so you don't have to type out the same "I'm doing fine" message to each person), to gps- and web-linked live tracking. Terrain dependent, we rarely had to wait more than five minutes to acquire a satellite, and it will confirm whether your messages sent or not. While we didn't trigger the SOS button in the field, we liked its design. We also appreciate that the latest iteration of this device makes it difficult to accidentally send a signal, but it is not challenging to use it quickly if you ever need to.

The Explorer+ is expensive at the outset, but worth it if you want to send a lot of messages in the field. Garmin's unlimited text messaging plan is more cost-effective than a SAT phone, and the messaging functionality is better. You can still send messages from the device if your smartphone runs out of batteries, and it also has fully featured GPS capabilities and weather forecasting. If you don't need weather reports, a barometer or as much on-device navigation, the Garmin inReach SE+, has the same messaging capabilities but is $50 less at initial purchase. In use, we often prefer the stripped down InReach SE+. Everything we say about the explorer+ can be extrapolated to the SE+.

Read review: Garmin inReach Explorer+

Best Bang For your Buck

Ocean Signal rescueME PLB1

Ocean Signal rescueME
Best Buy Award

at Amazon
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Weight: 4.0 oz | Battery life: 24 hours
Dual frequency SOS transmission
COSPAS/SARSAT is very reliable
No annual fees
Easy to operated one-handed (even with gloves)
Lacks 2-way messaging
Lacks non-emergency messaging

If messaging is not important to you, and you're looking for an emergency signaling device only, the Ocean Signal PLB1 is your best option. It is a little expensive up front, but there are no annual fees or subscription plans required. It is also much smaller than the Garmin device. Its closest competitor is the ACR ResQLink+. The ACR is functionally the same, but is $10 more and both heavier and bulkier. The Ocean Signal broadcasts a distress signal on two radio channels (406 MHz / 121.5 MHz) to, respectively, a monitored satellite network and a local aircraft distress frequency.

The powerful transmission gets sent out on the military's reliable COSPAS/SARSAT network, but you don't get the piece of mind of being able to confirm, by a message, that someone has received your distress signal. The Ocean Signal PLB1 is a great option for purely SOS functions, but we do see more value in the Explorer+'s messaging and GPS capabilities, which make it a more useful product overall.

Read review Ocean Signal rescueME PLB1

Notable Up-and-Comer

GoTenna Mesh

GoTenna Mesh

at Amazon
See It

Weight: 1.6 oz | Battery Life: 24+ hours
Almost infinitely customizable "network"
Emergency use requires carefully curated network
Even with wider adoption, coverage will never be guaranteed

From a fresh startup, the GoTenna Mesh is an innovative entry to the wilderness communication field. Basically, a Mesh network is ground-based and built by users. Each device serves to connect the user's smartphone to other users' via GoTenna devices nearby. Messages can be relayed through other devices, unbeknownst to the owner or user of said relay device. Maximum range between individual devices is dependent on terrain, but GoTenna claims a maximum of 4 miles. Our testing revealed a max range of 3.2 miles. The maximum range of the potential communication network is determined by terrain but also by the number of devices in service.

With limited adoption currently, GoTenna is best suited for groups of people recreating in close proximity to one another. Large mountaineering expeditions, small groups of international travelers and hunting camp groups are possible applications. With wider adoption, Mesh could be a more viable option. With the unique technology and potential for growth, we must mention it here. However, educate yourself thoroughly on the limitations before trusting this new technology.

Read full review: GoTenna Mesh

select up to 5 products
Score Product Price Our Take
Editors' Choice Award
The best device on the market for this purpose.
A good value for year-round tracking if you don't need 2-way messaging.
Best Buy Award
A small, satellite-linked emergency communicator. For life-threatening emergencies, this is exactly what you need and nothing more.
A great, emergency-only messaging device.
This start-up company and product is unique, with great promise. With wide adoption the possibilities are great.

Analysis and Test Results

At a recent talk on risk management, world-renowned adventurer Will Gadd offered to buy a satellite messenger for those who can't afford their own. We're not sure he was serious, but his point is clear; emergency communication is now a part of the outdoor experience. Some of the world's greatest adventures take place beyond the reach of modern cell signal. To summon emergency assistance and to communicate more routine matters from these wild settings, special technology — like personal locator beacons and sat messengers — is required. We test that technology for you.

Additional Resources — This is a complicated subject. For further information read our personal locator beacon and satellite messenger buying advice. We also make sport-specific recommendations for all your wilderness electronic needs and wishes.

How Long Do Rescues Take?

The entire communication process, from SOS activation to notification of local Search and Rescue (SAR) resources can take just minutes to a couple hours. Local, on-the-ground SAR response will vary, regardless of the technology used to summon help, from minutes to days. Response time following notification depends on local financial and political factors, terrain, weather, and a whole host of other things. Educate thyself on the SAR resources where you choose to recreate.

The last place you want to scrimp and save is on emergency devices  but we'll take a bargain where we can find one. The rescueMe on the far left wins the value battle. The inReach  ResQLink+  and GoTenna all have their places.
The last place you want to scrimp and save is on emergency devices, but we'll take a bargain where we can find one. The rescueMe on the far left wins the value battle. The inReach, ResQLink+, and GoTenna all have their places.


Personal locator beacons or satellite messenger cost-effectiveness requires some careful examination. The initial purchase price is only part of the equation. Some devices require subscription plans that vary over time, making comprehensive comparisons are difficult. We can, though, make some authoritative recommendations.

For SOS/Emergency use only, the best value will be a device on the COSPAS-SARSAT network. Currently, the Ocean Signal rescueME PLB1 is our Best Buy award winner for its access to the proven and free international satellite SAR network and for its tiny size. For a few bucks more and a bit extra weight the ACR ResQLink+ offers similar functionality. Currently, at initial purchase, the Garmin InReach explorer+ costs three times as much as the SPOT Gen3. Bargain shoppers, though, take note. Currently, in May of 2018, the subscription plan costs vary significantly. Assume 5 years of coverage with the least expensive service plan, and the gap between the SPOT and inReach closes significantly. In this way, the inReach's total cost after 5 years is only $20 more than that of the SPOT. For that additional $4 a year you get way better functionality, reliability, and coverage.

Screen shot of locating someone using the InReach. The message bubbles are when we sent a location when we got to camp. The connected dots are when the tracking feature is turned on.
Screen shot of locating someone using the InReach. The message bubbles are when we sent a location when we got to camp. The connected dots are when the tracking feature is turned on.

SOS Emergency Messaging

Sending an emergency signal is the primary reason to carry a communication device into the wilderness. It's also the metric that unites the category. All of these devices, with varying degrees of effectiveness, can be used to summon help in the event of a life or limb emergency. SAR experts confirm that the most important information to relate is 1. where you are and, 2. how bad it is. When you push the SOS button a personal locator beacon, you are sending dispatch your GPS coordinates and saying "this is really, really bad." The gravity of the situation is implied by the uncertainty in a simple "help" notification. With SOS transmission you are saying "get here as fast as possible".

Of course, being able to relate more nuanced information and being able to answer questions from SAR responders is of great value. Satellite messengers or PLBs that that allow two-way, customized communication improve emergency response.

The ACR ResQLink+ and Best Buy Ocean Signal PLB1 both use the COSPAS-SARSAT system. Functionally, for emergency messaging, these two are identical. The SPOT Gen3 and Garmin inReach use private networks and emergency dispatch systems. Aside from coverage differences, elaborated below, they work the same for SOS messaging. The Garmin inReach adds significant functionality with two-way, customized messaging. With some thought and care, the less-urgent "help" message option on the SPOT Gen3 can be leveraged for emergency use. Finally, to summon help in an emergency with the GoTenna requires that you are texting within a "Mesh" network that overlaps with cell signal. In an emergency, coverage allowing, you will text someone who has cell signal who can forward, usually by telephone, relevant information to dispatch. This works, but not nearly as well as the others. In short, the inReach is the best for emergency messaging, because of the opportunity to send and receive more nuanced information in an emergency. For "send help now" signaling, the Ocean Signal, ACR, and SPOT are basically the same and have long been proven to work.

There are three major types of emergency messaging networks used by devices in our review.
  • Public — The COSPAS-SARSAT satellite network is a product of international, government cooperation. Tax dollars fund it and it is free to use. It has provided satellite SAR support for more than 30 years. This network covers the entire planet and, with infrequent exceptions, is for emergency use only.
  • Private — These are for-profit services operated by a corporation. One example is Globalstar, the network that supports SPOT devices. It currently does not cover the entire world. See Globalstar and SPOT literature for an up-to-date coverage map. Another example is Iridium, which supports the Garmin inReach. It covers the entire planet and its track record over the past 5-6 years has been less blemished than that of Globalstar's. The Iridium-supported device we tested worked more reliably than the Globalstar-supported devices.
  • Network — This is a relatively new system used by GoTenna Mesh. It is a start-up, terrestrial, "crowd-sourced" communications network. At current adoption levels, it is only suitable for use by a group of friends in fairly close proximity. With wider adoption, multiple groups and users could overlap enough to provide for adequate coverage.

Location information is easily shared and can be viewed on various map types  available for offline storage  within the GoTenna app.
Location information is easily shared and can be viewed on various map types, available for offline storage, within the GoTenna app.

Non-Emergency Messaging

Non-emergency messaging takes multiple forms on these devices. Some offer texting and location services that simulate smartphone functionality. Others provide the ability to send a simple "I am here and I am ok" note. Some offer no option for non-emergency messaging at all. There is a wide range of features and performance. A different sort of non-emergency messaging is location tracking. Some devices can be configured to automatically send, on some preset interval, your location and a sort of implied status update.

Navigation — Tested devices vary widely in functionality. That wide range covers many different types of communications, from emergency-only to live-stream tracking of your wilderness progress. It also includes different degrees of navigational function. Some of the tested devices can be used for GPS navigation. For a variety of reasons, we confined our testing to the communication attributes of the reviewed products.

We love multi-purpose equipment, but combining navigation and communication in a single device is a little problematic. First, emergency communication is an important thing. Complicating your device, your usage, and your battery consumption with navigation compromises your communication capability. Next, no matter how well made the navigation interface of your communication device, there is a better solution. Navigating on a dedicated hand-held GPS device or with a carefully set-up smartphone app and protocol will be much easier and clearer than on your satellite messenger.

Looking at it a different way, there are three major types of non-emergency messaging. First, there is two-way texting with or without location data attached. This is, of course, the most useful. Next, there is the transmission of manual "ok" messages, usually with location data attached. Finally, there is automated "tracking". Automated tracking is a function in which the device, on some predetermined time interval, will send location information to a front country correspondent. All these different sorts of messaging can go to web interfaces, phone numbers, or email addresses.

Tracking Data Is Tricky — Some devices can be configured to passively send a stream of location information, through a web interface, to a responsible civilian in the front country. Say a mountain biker gets in the habit of initiating tracking before descending. In the event of a crash in which he loses consciousness the location of his stop point is noted. The person at home must be watching closely enough to see that, and where, the signal has stopped moving. This is a fairly tricky task, given the resolution of this tracking feature. The main issue is that there are multiple routine occurrences that could falsely appear, to the emergency contact, like a bad crash like losing the satellite signal, a dead battery, or a long lunch.

Bottomline: Tracking data can help locate someone if they are overdue, but that overdue status must be determined by other means. Your trusted emergency contact in civilization must be educated and empowered to secure help but must do so understanding the realities of wilderness travel and the limitations of communications.

The InReach explorer+ provides all forms of non-emergency communication. It leads the market and leads our test, primarily for this reason. The SPOT Gen3 has just two options for non-emergency communications. It has a preprogrammed "OK" message functionality, with location data attached, and it has a few different tracking mode configurations. The GoTenna Mesh only offers intuitive two-way texting and location sharing, provided you participate in or have built a good network. It has no default SOS button. The Best Buy Ocean Signal rescueME PLB1 is the opposite. It has only an SOS button and no non-emergency messaging.

The Garmin InReach works seamlessly with a smartphone app to send and receive text and location information.
The Garmin InReach works seamlessly with a smartphone app to send and receive text and location information.

The ACR ResQLink+ offers no explicit non-emergency messaging. It does offer an inexpensive subscription to 406Link, to test the device that sends notifications to friends and family, sometimes with location data attached. This is nuanced, read the full ACR review for elaboration.

Signal Coverage

Each communication network has coverage limitations, and all satellite communications have inherent restrictions. Additionally, we found differences, even when coverage seemed intact, in the reliable transmission of sent messages. Because all remote communications are fraught, communication reliability is greatest when it can be "two-way". We know from experience with one-way devices that the field user can be "sending" messages that no one is getting. When the communications are "two-way", confirmation of receipt is a little clearer.

Activating the SOS feature of the ACR ResQLink is as simple as deploying the antenna (which otherwise covers the SOS button)  placing the device with the best possible "view" of the sky  and pressing the emergency button. It must sit there  undisturbed  for as long as possible. Ideally you leave it there until help arrives.
Activating the SOS feature of the ACR ResQLink is as simple as deploying the antenna (which otherwise covers the SOS button), placing the device with the best possible "view" of the sky, and pressing the emergency button. It must sit there, undisturbed, for as long as possible. Ideally you leave it there until help arrives.

Satellite Coverage — Terrain, vegetation, and electronic interference compromise message transmission effectiveness, geographically and temporally. Some places have no satellite coverage ever. Other places will have windows when the signal is in and out.

For reasons we hope are obvious, we could not and did not test the coverage and effectiveness of SOS messaging. Each device allows a sort of test mode, but this does not activate the entire SOS system on any device. Those of us who have not yet had a backcountry emergency have to trust the manufacturers and the experience of other, less fortunate, users. For these ratings, we rely on research. Lots and lots of research.

Both the ACR ResQLink+ and the Ocean Signal rescueME PLB1 use the same network and communication protocol. Both can be tested, but the number of tests are limited by battery life. The ACR offers a subscription plan that will confirm the results of each test via email and cell phone. The Ocean Signal rescueME confirm its functionality with on-device lights. This is less comforting as it doesn't involve satellite confirmation. Decades of use and anecdotal evidence confirms the global coverage and effectiveness of the COSPAS-SARSAT system that these two devices employ. Aside from institutional knowledge and the basic testing we performed, we have no way to definitively test signal coverage of these two devices.

Size reference of the ACR ResQLink+. Shown here with the antenna deployed. This photo was captured during testing of the ACR. The green light above the "L" in Link indicates successful communication with satellites.
Size reference of the ACR ResQLink+. Shown here with the antenna deployed. This photo was captured during testing of the ACR. The green light above the "L" in Link indicates successful communication with satellites.

The other three devices are easier to test for range and coverage using their non-emergency communication options. Our goal was to verify manufacturer claims. We found that by sending non-emergency messages from each, the SPOT, InReach, and GoTenna work as intended. The SPOT's satellite network covers the major terrestrial wilderness destinations of an American adventurer. The inReach uses a satellite network with global coverage. Within the inherent limitations of all satellite comms, the inReach truly does work everywhere we've tested it.

Finally, the GoTenna employs an entirely different communication network. In short, for now, it works where you and your friends have "built" a ground-based network. There are ways to customize your network and ways to cooperate with other users, but coverage is far less robust than all the other technologies we tested. GoTenna claims that device-to-device range is up to 4 miles, as long as the terrain is open. In our testing we found 1:1 device range to be as low as 0.6 miles in mountainous terrain, with a confirmed 3.2-mile range on the flat bottom of Idaho's Teton Valley. See the full GoTenna review for more information.

The result of our most successful GoTenna range check. In this case  in the flat terrain of Idaho's Teton Valley  we successfully swapped messages from a confirmed 3.2 miles apart.
The result of our most successful GoTenna range check. In this case, in the flat terrain of Idaho's Teton Valley, we successfully swapped messages from a confirmed 3.2 miles apart.

We also found subtle differences in message integrity. We used the SPOT Gen3 side-by-side with the Garmin inReach throughout the test, recording the time needed for standalone messages to be received by contacts and confirmed as sent. The inReach messages were received faster than the SPOT messages about 60 percent of the time, with the inReach messages either confirmed as failed or received within 20 minutes almost always. The SPOT messages confirmed as failed only 45 minutes after the send attempt at times, and were sometimes received more than two hours after the initial send. The inReach, when paired with a smartphone, also allows the user to watch the progress of the message with a clear visual confirmation. This is a lot nicer than trying to decipher the blinking lights on the SPOT, wondering if the message was sent or not. Since the chief feature of the SPOT is its ability to send messages to your contacts, and the inReach performs message sending so much better, the inReach is quite clearly a superior device for this purpose.

Anywhere within its limited signal coverage, the GoTenna reliably delivered messages and the app provides delivery confirmation.

On each COSPAS-SARSAT device are basic activation instructions. ACR ResQLink on the left  Best Buy OceanSignal PLB1 on the right.
On each COSPAS-SARSAT device are basic activation instructions. ACR ResQLink on the left, Best Buy OceanSignal PLB1 on the right.

Ease of Use

PLB and sat messenger ease of use is a function of set-up procedure and in-the-field interface clarity and options. Set up complication ranges from a simple, one-time online form to an ongoing process of charging and deploying devices to remote locations. In-the-field interfaces are either a few buttons on the device, accompanied by flashing lights that must be decoded, or a paired smartphone app from which one can communicate and deduce various status information.

First, let us look at set up of each device. The COSPAS-SARSAT devices (ACR ResQLink+ and Ocean Signal PLB1) have identical set up procedures. You fill out an online form and await the arrival, via mail, of your free registration sticker. Through the online interface, you can make changes down the road if needed.

Set up of the SPOT Gen3 and the Garmin inReach is similar. Both require online interaction and selection of a subscription plan. Both can have various features that you can opt into or out of. With both the SPOT and the inReach you can and should tailor the address list that receives your "ok" messages and tracking notifications to each trip separately. The inReach has an app and associated Bluetooth tethering. Setting up the GoTenna Mesh into its simplest configuration is basically the same as with any other modern personal electronic device — charge it, download the app, and follow syncing and configuration instructions on the app. However, to build a truly effective GoTenna network requires further work and planning.

In use, the COSPAS-SARSAT devices are super simple. For most people in most settings, the device will live in your emergency kit for years and years with no changes, maintenance, or deployment. The batteries are fixed and long-lasting. Since the only features are for emergency use, few will actually use the device at all. Both the ACR ResQLink and the Best Buy Ocean Signal PLB1 have rudimentary instructions printed right on the device. The instructions are accurate. For SOS use, the SPOT Gen3 and InReach explorer+ are almost as simple as the COSPAS-SARSAT devices. Simply activate the SOS mode. Sending a preprogrammed "ok" message from either device is similar.

Benja texts  from his smartphone  through the GoTenna Mesh. The GoTenna sits on the log next to him.
Benja texts, from his smartphone, through the GoTenna Mesh. The GoTenna sits on the log next to him.

Using the two-way, customizable messaging attribute of the Garmin inReach requires further effort but is well worth it. Sending customized messages directly from the device is slow, but it works. Sending customized messages from the app is far more user-friendly. In this context, using your smartphone's familiar keyboard truly leverages the best attributes of the inReach.

When coverage is ample and you are sending 1:1 messages, the GoTenna is very simple. However, to build and maintain a network that fully leverages the meshing capability of this technology requires an engaged and savvy user. There are many ways to optimize the function of the GoTenna Mesh and all require that the user is well-versed in just how this technology works.

Here are the rescueMe  inReach  ResQLink+ and GoTenna compared. The un-pictured SPOT is about the same size as the rescueMe.
Here are the rescueMe, inReach, ResQLink+ and GoTenna compared. The un-pictured SPOT is about the same size as the rescueMe.


Going to the wilderness usually requires packing light. Therefore, portability of your communications device(s) is important. Portability, for our purposes, is a function of weight and bulk.

The Garmin InReach explorer+ is the largest and heaviest product we tested. It also does way more than everything else we tested. Its function is disproportionate to its size, and it does enough that we don't mind its additional weight. The inReach is almost twice as heavy as both the SPOT Gen3 and the Best Buy Ocean Signal rescueME. The ACR ResQLink+ is about halfway between the weight and size of the inReach and the SPOT.

One GoTenna Mesh device is less than half the weight of the next closest competitor and is an easily packed narrow profile. However, a team needs multiple Mesh devices to leverage their effectiveness. And, of course, the Mesh network covers far less territory than the other products we assessed.

These two devices function and perform exactly the same way. The PLB 1 is smaller  lighter  and less expensive. For these advantages  and the overall value of this style of device  it gets our Best Buy award.
These two devices function and perform exactly the same way. The PLB 1 is smaller, lighter, and less expensive. For these advantages, and the overall value of this style of device, it gets our Best Buy award.

The ACR ResQLink+ and Ocean Signal rescueME PLB1 are basically identical in function. The only functional difference is that the ACR floats on its own, while the Ocean Signal requires a flotation pouch. This difference is minor. The major difference between them is size and weight. The Ocean Signal is smaller and lighter, earning it our Best Buy award, just ahead of the ACR ResQLink.

Another angle on the bulk difference between the ACR ResQLink (right) and the PLB1.
Another angle on the bulk difference between the ACR ResQLink (right) and the PLB1.


Choosing a personal locator beacon or satellite messenger is an important choice and a complicated one. Your options are distinguished by competing considerations of price, weight, bulk, functionality, and network coverage. There is no one product that we can truly recommend for everyone, even if cost is not a concern. This means that your choice requires careful attention and thorough self-education.

Other Remote Communication Options — Here are a few communication options that we omitted.
  • Satellite phones — Devices that can transmit voice over satellite signal are more expensive and usually bulkier than what we tested here.
  • Two-way radios — Require significantly more user education to emulate the clarity, coverage, and convenience of the devices we test here.
  • Nautical Options — There are many nautical devices that use some of the same technology and protocols. We did not test them.

Jediah Porter and Chris McNamara

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