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How to call for help at sea

Do you know who to call in an emergency? Do you have the right equipment? Whether you’re at the coast, on the water, or further out to sea, we have everything you need to know so you can call for help in an emergency.

Beacons or devices? How to call for help

Photo: RNLI/Nigel Millard

No matter if you’re walking along the coast, angling from rocks, out on your kayak, or sailing further out to sea, having the means to call for help in an emergency can be the difference between life and death. In most cases, a mobile phone can be enough to call for help. But is your mobile phone protected if you unexpectedly found yourself in the water?

If you are out on the water or further offshore, you might not be able to get a signal on your mobile. More specialist equipment may be needed to ensure that, if an accident happens and you find yourself in danger, you can alert the authorities and have them come rescue you.

In this guide, we cover all the different ways you can call for help. We’ll also explain the equipment you need for different activities, so you can make sure you are prepared if an incident happens.

Ocean Sailor Pip Hare using a VHF radio

Photo: RNLI/Nathan Williams

Ocean Sailor Pip Hare using a VHF radio

Who to call for help

If you find yourself in an emergency situation or spot someone else in trouble, you should call 999 or 112 and ask for the coastguard. 

If you are inland and see someone in difficulty on the water, be it on a river or a lake, you should ask for Fire and Rescue when you call for help.

Calling for help

There are a number of different products that can be used to call for help. With all water activities, we strongly encourage you to take a means of calling for help that is most suitable for your activity. We advise that you make sure you know how to use it, and keep it within reach at all times.

Mobile phone

How to call for help with a mobile phone

If you are at the coast or taking part in an inshore activity such as kayaking, then a mobile phone might be the best and easiest means of calling for help, as you are likely to have one anyway. You should ensure your phone is fully charged before heading out, and might want to take a portable charger.

  • Keep your mobile in a waterproof pouch. You should carry  this on your person so it’s within easy reach – it’s no use if you can’t reach it.
  • Smart phones can provide a location, but emergency calls should be made by voice (call 999 or 112 and ask for the Coastguard). Text messages and map locations are often no use to the Coastguard.
  • Even if your phone shows no service, try calling 999 or 112 anyway as in an emergency your phone will be able to use another phone network. Please note that with some devices, repeatedly pressing the power button can activate an emergency call with your location.
  • The RYA SafeTrx app can be used to log, track and send alerts about your trip. Visit

Personal Locator Beacon (PLB)

How to call for help using a personal locator beacon

PLBs use search and rescue satellites to send a message to the Coastguard that clearly says you’re in trouble. The Coastguard then sends search and rescue assets out to the GPS position given from the PLB.

They work on the 406MHz distress frequency. The beacon also operates using a 121.5MHz frequency, which means lifeboats can home in on the device once they get closer. Importantly, a beacon is a recognised way of calling for help. 

PLB benefits:

  • Unlimited range, so you can get help from anywhere in the world with this beacon. If you’re considering going anywhere outside A1 GMDSS sea area, the PLB is the one for you.
  • As a beacon is a recognised way of calling for help, you can rely on an immediate reaction from the Coastguard.

PLB limitations:

  • Manual activation only, so you must be conscious and able to hold it up out of the water with the antenna pointing at the sky. They aren’t made to float.
  • It needs to be registered with the Coastguard. It belongs to you only, so you shouldn’t lend it to friends.

Automatic Identification System (AIS)

How to call for help using an AIS device

AIS devices use VHF frequencies to transmit their location which can be picked by all AIS receiving stations within range, including commercial ships and other leisure vessels. The device does give a location but isn’t the recognised way of calling for help. AIS devices have a range of up to 5 nautical miles in open water.

AIS device benefits:

  • If you fall overboard, especially in the dark, it gives your crew the power to find you quickly.
  • When that AIS device goes off, everybody in the vicinity (around 5 miles in open water) who has an AIS receiver onboard will be able to see where you are. They are likely to assume it’s a call for help. Ocean Sailor Pip Hare has seen this work in practice: ‘I was recently sailing along the Dutch coast when someone’s personal AIS device went off accidentally. Almost immediately, three vessels in the vicinity notified the coastguard and then one of them radioed our vessel to see if it was us.’
  • They can be automatically activated. Automatic and semi-automatic ones will activate even if you’re unconscious.
  • It doesn’t need to be registered. You can loan it to others.
  • The latest development in AIS device technology is the inclusion of DSC in some packages. So your crew will hear a DSC alert, even if they don’t get an AIS audible signal. Some can also send out an all-ships distress alert, depending on the country.

AIS device limitations:

  • Range of around 5 miles in open water. Because it uses VHF, the closer you get into the coast or any obstruction, then the lower that range will be. Even in A1 on the GMDSS sea area map, it’s possible that the AIS may not reach anyone.
  • It’s not an internationally recognised way of calling for help. The Coastguard does not recognise it as a call for help. Currently, the Coastguard doesn’t get an audible alarm, or an emergency signal.
  • Not all AIS receivers display the same information (depending on chart plotter, software updates and AIS receiver). The latest kit gives an audible alarm and circle with cross. Many sets won’t do an audible alarm. Some sets won’t even see the symbol. Test your kit to check (inform the Coastguard first)

Handheld VHF/DSC (Very High Frequency/Digital Selective Calling)

How to call for help using a handheld VHF radio
  • If possible, buy a DSC-equipped radio (some are not). A DSC distress alert is a recognised emergency signal, and it also transmits your location.
  • Send a distress alert followed by a mayday voice call on Channel 16. This communicates the distress message to all vessels and shore stations in range.
  • Requires an operator’s licence, a ship’s portable radio or ship’s radio licence (free in the UK if requested online) and a Maritime Mobile Service Identity (MMSI) number, which comes with the radio licence

Emergency Position Indicating Radio Beacon (EPIRB)

How to call for help using an EPIRB

An EPIRB works in a similar way to a PLB, however they are usually a lot bigger. You must register the EPIRB with the vessel you are using. It is not registered to a person like a PLB, and if you change vessel, then you will have to re-register. The battery life of an EPIRB tends to be longer, normally for a minimum of 48 hours.’

The distress signals are passed to the relevant maritime rescue coordination centre, which will launch the search and rescue services.

Key features of an EPIRB:

  • Recognised emergency signal
  • can be float-free, automatic or manual
  • must be registered
  • always choose a GPS-enabled EPIRB
  • can be dropped next to a man overboard to mark their position
  • fitted with a flashing light
  • radio direction finding equipment can be fitted and used to home in on to beacon
  • transmits for 48 hours plus.


How to call for help using a tracker

Some GSM or satellite trackers have an SOS function which allows you to call for help from a Rescue Coordination Centre (RCC). They will then pass on your distress message to the Maritime RCC who will task the appropriate rescue service for you.

All trackers are different and costs, specifications and network availability vary.