| What it does | One-way SOS with location |
| Via | Cospas-Sarsat SAR satellites |
| Subscription | None required |
| Limitation | SOS only, no messaging |
A personal locator beacon (PLB) is an emergency device that, when activated, sends a one-way distress signal with your GPS location to government search-and-rescue services via the global Cospas-Sarsat satellite network. PLBs need no subscription, work worldwide, and are a reliable last-resort SOS — but they only call for help, with no two-way messaging.
How it works
Activate it and it beams your location to official rescue agencies — subscription-free, unlike a satellite messenger.
PLB vs satellite messenger
PLB = pure SOS; messenger = two-way texting too. See PLB vs satellite messenger.
Frequently asked questions
What is a PLB?
A personal locator beacon is a compact emergency device that, when you activate it, transmits a distress signal and your GPS coordinates to government search-and-rescue agencies through the international Cospas-Sarsat satellite system. It's a dedicated, last-resort way to summon rescue from anywhere on Earth.
PLB vs satellite messenger?
A PLB sends a powerful one-way SOS to official search-and-rescue with no subscription, and is highly reliable for emergencies only. A satellite messenger (like an inReach) adds two-way text messaging, tracking, and check-ins but requires a paid subscription. Many choose a messenger for communication, a PLB for pure SOS reliability.
Do PLBs require a subscription?
No — that's a key advantage. PLBs use the free government Cospas-Sarsat system, so there's no ongoing fee; you just register the device. Satellite messengers, by contrast, need a paid subscription to send messages and SOS.
Sources
- Emergency beacons — National Park Service