What Is a PLB?
What Is a PLB? — Plain English Guide
These are my favourite articles. I tried to explain this to my friends grandmother and got nowhere.. I hope I have improved. A PLB is a personal EPIRB that goes wherever you go. That is genuinely the simplest way to explain it. Where an EPIRB stays with the vessel, a PLB goes on you — clipped to your lifejacket, in a pocket, attached to your kit.
The Plain English Version
A PLB — Personal Locator Beacon — is a small handheld device that transmits a distress signal via satellite when activated. It is registered to you as a person, not to a vessel. When you press the button it tells the coastguard exactly who you are and exactly where you are.
The key difference from an EPIRB: if you go overboard and the vessel sails on without you, the EPIRB goes with the vessel. The PLB goes with you. In a man overboard situation, that distinction is everything.
How Does a PLB Work?
Same principle as an EPIRB. When activated it transmits on 406MHz to the Cospas-Sarsat satellite network. Your GPS position and unique registration details are relayed to the nearest rescue coordination centre — in UK waters, HM Coastguard. Rescue services are dispatched to your exact location.
PLBs must be activated manually — unlike Category 1 EPIRBs, PLBs do not activate automatically on water immersion. You need to be conscious and able to press the button. This is why wearing a PLB on your lifejacket rather than storing it in a bag matters.
One important 2026 update: it is now a legal requirement to register all 406MHz PLBs carried on UK-flagged vessels and powered watercraft. Registration is free at beaconregistration.admiralty.co.uk.
How Is a PLB Different from an EPIRB?
Three key differences:
Registered to a person not a vessel — your PLB travels with you, not with the boat.
Manual activation only — PLBs do not self-activate. You press the button.
Smaller and lighter — designed to be carried on your person or lifejacket rather than mounted on a vessel.
Transmits for 24 hours minimum rather than 48 hours for an EPIRB.
Who Actually Needs a PLB?
I have not personally carried a PLB offshore — though I know plenty of people who have and some commercial operations require them. People look after them properly when they have them. They treat them like their lifejacket. Some people grumble about having to put them on and I understand that — it can feel like one more thing to clip to yourself. But the logic is simple: if you are already wearing a lifejacket for safety, adding a PLB takes about five seconds and significantly improves the chances of being found if the worst happens.
My honest view on who needs one:
Anyone doing a night watch on a long offshore passage — absolutely. If you go overboard at night you need something that works even if no one sees you go.
Anyone working commercially offshore — many operations require them. Follow the requirement.
Anyone sailing solo — non-negotiable. There is nobody else to raise the alarm.
Anyone going more than a few miles offshore — worth serious consideration.
Weekend coastal sailing close to shore with other traffic around — lower risk, but the question is always: why not?
Where Should You Carry It?
On your lifejacket — the most effective position because it means you have it with you if you go overboard unexpectedly. Most modern lifejackets have a dedicated PLB pocket or attachment point. If yours does not, a clip on the lifejacket webbing works fine.
Not in a bag. Not in the cabin. On you — when you are on deck.
Our Recommended PLBs
Ocean Signal rescueME PLB1 — Our Top Pick
The world’s most compact PLB — genuinely small enough to fit in your palm. Engineered and manufactured in the UK. GPS enabled, waterproof to 15 metres, 7 year battery standby life, and operates from -20°C to +55°C which matters if you are working in the North Sea in winter. The spring loaded activation button prevents accidental activation. Simple, reliable, trusted.
McMurdo FastFind 220 — Best Budget Option
Straightforward, proven, and the most accessible price point in this category. One button activation, GPS and Galileo GNSS positioning, 121.5MHz homing signal, and a flashing SOS LED for visual location. Heavier than the Ocean Signal at 340g and not inherently buoyant so use with a flotation collar for marine use. Does exactly what it says on the tin — there is a verified account of this unit saving a life during a stroke emergency at sea. Simple, Reliable.
ACR ResQLink AIS PLB-450 — Best with AIS
This is the most capable PLB on the market right now. It combines global satellite rescue with AIS — meaning nearby vessels within a 5 mile radius receive your distress signal immediately as well as the coastguard. ACR has been making rescue beacons since 1956 and their kit is used by NASA and the US Military. The Return Link Service confirms your distress signal has been received — genuine peace of mind when you need it most.
FAQs
Does a PLB need a subscription?
No. Registration with the UK Beacon Registry is free. The Cospas-Sarsat satellite network is government funded and free to use. No ongoing costs after purchase.
How long does a PLB battery last?
Modern PLBs have a 5 to 7 year battery standby life. Once activated they transmit for a minimum of 24 hours. Battery replacement must be carried out by an authorised service centre — check the expiry date on the device.
Can a PLB be used on land?
Yes. PLBs work globally on land or sea. Hikers, climbers, and remote workers use them. The principles are identical — activate and the satellite network contacts the appropriate rescue authority for your location.
Can I test my PLB?
Yes — using the built-in self-test function only. Never fully activate it unless it is a genuine emergency.
The information in this article is for general guidance only and does not constitute professional safety advice. Always verify current PLB registration requirements at beaconregistration.admiralty.co.uk and gov.uk/mca. marinesafetyguide.com participates in affiliate programmes including Amazon Associates and the Awin network and may earn a small commission on purchases made through links on this site, at no extra cost to you.
