How to Send a MAYDAY Distress Call on Marine VHF Radio

A MAYDAY is the most serious call you will ever make from a vessel. This guide walks through the exact procedure — channel, words, order, what to say if you forget — so you can do it correctly on the worst day of your sailing life. With a free interactive VHF/DSC simulator at the bottom so you can rehearse it safely until your hand stops shaking.

Published 14 May 2026 · 8 min read · Reviewed by SkipperCheck maritime instructors

When to send a MAYDAY (not PAN-PAN, not SÉCURITÉ)

The ITU Radio Regulations define MAYDAY as a call indicating that a station or person is threatened by grave and imminent danger and requests immediate assistance. In plain English: someone could die, or the vessel could be lost, very soon, without help.

Three categories of safety call exist on marine VHF, and they are not interchangeable:

• MAYDAY — grave and imminent danger to life or vessel. Examples: vessel sinking, on fire, abandoning ship, person overboard in conditions that threaten life. Triggers the highest possible response and silences Channel 16 for distress traffic only (SEELONCE MAYDAY).
• PAN-PAN — urgency. Serious but not immediately life-threatening. Examples: medical advice required, engine failure in busy waters, lost rudder, drifting in shipping lanes. Coast stations will respond and may arrange tow or medical guidance.
• SÉCURITÉ — safety. Broadcasting a navigational hazard or weather warning to all vessels. Examples: lost containers spotted, navigation buoy missing, gale warning.

Under-grading the situation can delay rescue. If you are in doubt, send a MAYDAY — coastguards would rather respond to a precautionary MAYDAY than miss a real one.

Step 1 — Press the DSC distress button

Modern marine VHF radios fitted with Digital Selective Calling (DSC) have a guarded red DISTRESS button on the front panel. Pressing it sends an automated digital alert on Channel 70 containing your MMSI and (if connected to a GPS) your position, then auto-switches the radio to Channel 16 for voice follow-up.

• Lift the red guard cover. It exists specifically to prevent accidental presses.
• Press and hold for at least 5 seconds. Most radios display a countdown and emit a tone. A brief tap will not trigger the alert — this is intentional.
• The alert auto-repeats every 3.5–4.5 minutes until a coast station sends a digital acknowledgement, so you don't need to repress it.
• If your radio menu offers a Nature of Distress selection (fire, flooding, sinking, abandoning, MOB, collision, grounding), pick the closest match before the 5-second hold. If you don't have time, the default "undesignated" alert is always valid (ITU Radio Regulations Article 47).

Step 2 — Switch to Channel 16 and check power

If your radio has DSC, it should auto-switch to Channel 16 after the alert. If not, select Channel 16 manually. Confirm:

• Power: HI (25 W) — maximum range to coast stations and other vessels. Some radios default to LO (1 W) for short-range calls; switch back to HI for distress.
• Volume: audible — you need to hear the response. Stress can make you forget basic settings, so check the SQL (squelch) and VOL.
• Mic in hand, PTT ready — practise pressing PTT, waiting a second for the radio to settle, then speaking. The first second of any transmission is often lost.

Step 3 — Say MAYDAY MAYDAY MAYDAY + ITU sequence

The voice MAYDAY follows a fixed order. Memorise it. Under stress, you will skip parts — but practising the order in advance dramatically increases the chance you get everything in.

1. "MAYDAY, MAYDAY, MAYDAY" — three times. Triggers Channel 16 silence (SEELONCE MAYDAY) and signals genuine distress.
2. "THIS IS [vessel name], [vessel name], [vessel name]" — vessel name spoken three times so the call sign is unmistakable.
3. "MMSI [9-digit number]" — if known. Coast stations match this to the DSC alert and Ship Radio Licence database.
4. "MAYDAY, [vessel name]" — short repetition for any station that missed the opener.
5. POSITION — latitude and longitude, or bearing and distance from a named navigational mark/harbour. Example: "MY POSITION IS 56 30 5 NORTH 021 45 3 EAST" or "POSITION 5 NAUTICAL MILES SOUTH OF VENTSPILS HARBOUR ENTRANCE."
6. NATURE OF DISTRESS — what's happening. Plain English: "I AM SINKING", "ON FIRE", "MAN OVERBOARD", "TAKING ON WATER", "ABANDONING VESSEL", "COLLISION", "GROUNDING."
7. PERSONS ON BOARD — number. Example: "FIVE PERSONS ON BOARD."
8. ANY OTHER RELEVANT INFORMATION — vessel description, life raft launched, EPIRB activated, persons injured, time available before sinking, etc.
9. "OVER" — signals you are listening for a response. Release PTT.

Full example MAYDAY call

Here is a complete MAYDAY for a 12 m yacht Sirius taking on water 5 NM south of Ventspils:

Coast station response (within ~15 seconds):

From here the coast station coordinates the rescue — dispatching a lifeboat, helicopter or diverting nearby vessels. Stay on Channel 16, maintain a continuous watch, and respond to all coast station instructions.

Common mistakes that cost you minutes

• Skipping the DSC alert because you went straight to voice. The DSC alert sends your position and MMSI digitally in under a second — significantly faster than the voice call. Always do both if equipped.
• Pressing PTT before mic settles — the first second is often lost. Press, wait half a second, then speak.
• Forgetting persons-on-board — the coastguard needs this to size the response. If a helicopter is dispatched, the crew size determines payload planning.
• Saying "MAYDAY" twice instead of three times — three is mandated by the ITU procedure and recognised by automated coast station systems.
• Confusing MAYDAY with PAN-PAN under stress — under-grading delays rescue. If life is at risk, MAYDAY.
• Speaking too fast — coast stations are reading position digits and may need them repeated. Speak each digit clearly: "FIVE SIX DEGREES THREE ZERO POINT FIVE MINUTES NORTH" — not "fifty-six thirty point five north."
• Pressing distress accidentally without cancelling — an unintended DSC alert is a Search and Rescue event somewhere. If you accidentally fire one, immediately voice on Channel 16: "ALL STATIONS, THIS IS [vessel name], MMSI [number]. CANCEL MY MAYDAY OF [time]. NO DISTRESS. POSITION [your position]. OUT."

After the call — what happens next

1. Maintain continuous watch on Channel 16. The coast station may need to verify position, request status updates, or relay instructions from rescue assets.
2. Stay on the radio, not on the mobile phone. Coastguards work via VHF; switching to mobile creates information silos.
3. Listen for SEELONCE MAYDAY — the coast station enforces radio silence on Channel 16 for distress traffic only. Other vessels stop routine calls.
4. Prepare for handoff to rescue assets — life raft ready, lifejackets on, EPIRB armed (or already activated), grab-bag near the companionway.
5. Be ready to relay information to inbound assistance — your colour, drift direction, persons injured, anyone in the water. Helicopters and lifeboats use visual handoff once on scene.
6. If the situation improves and assistance is no longer required, the coast station will broadcast SEELONCE FEENEE to lift radio silence. Don't lift it yourself.

Practise it without alerting the coastguard

The best time to learn the MAYDAY procedure is not at 0300 with smoke in the cabin. The procedure has to be muscle memory before you ever need it.

SkipperCheck provides a free interactive VHF/DSC simulator in your browser — same realistic radio interface, same DSC distress button, same voice protocol — so you can rehearse the entire MAYDAY without contacting any real coast station. The first scenario in the free demo set is exactly this: a voice MAYDAY call from a sinking vessel. Press PTT, read aloud, hear the simulated coast station respond.

For the full 15-scenario library — including Mayday Relay, DSC routine calls, Pan-Pan engine failure, and receiving incoming DSC distress alerts — combined with the online VHF Short Range Certificate (SRC) course, see the VHF SRC Certificate Online Course (€199, certificate issued by NAUTICA SIA, aligned with CEPT/ERC/REC 31-04 and ITU Radio Regulations).

FAQ

What channel do I use for a MAYDAY call?

Channel 16 (156.800 MHz) is the international VHF distress, urgency and calling channel. Send the voice MAYDAY on Channel 16. If your radio has DSC, the digital alert is sent automatically on Channel 70 before the radio auto-switches to Channel 16 for voice.

How long do I hold the DSC distress button?

Press and hold for at least 5 seconds. Most radios show a countdown and emit a tone. The alert then auto-repeats every 3.5–4.5 minutes until a coast station digitally acknowledges it.

Do I say MAYDAY twice or three times?

Three times. The triple repetition signals genuine distress (not urgency or safety), triggers Channel 16 silence (SEELONCE MAYDAY) from other vessels, and gives coast stations an unambiguous identifier.

What if I don't have a DSC distress button?

Skip directly to the voice MAYDAY on Channel 16. Ensure transmit power is HI (25 W) for maximum range. Re-transmit at 1-minute intervals until acknowledged. If MMSI is unavailable, omit it.

What is the difference between MAYDAY, PAN-PAN and SÉCURITÉ?

MAYDAY is for grave and imminent danger — immediate assistance required. PAN-PAN is urgency — serious but not immediately life-threatening (medical advice, engine failure in busy waters, lost rudder). SÉCURITÉ is safety — broadcasting a navigational hazard or weather warning. All three have priority over routine traffic; MAYDAY has the highest priority.

Can I practise sending a MAYDAY without alerting the coastguard?

Yes — use a marine VHF simulator. SkipperCheck's free VHF/DSC simulator has 3 demo scenarios (including voice MAYDAY) that run in your browser. You can press the red DSC distress button, hear the alarm tone, and rehearse the full procedure as many times as you need without contacting any real coast station.

What if I accidentally fire a DSC distress alert?

Immediately broadcast a voice cancellation on Channel 16: "ALL STATIONS, THIS IS [vessel name], MMSI [number]. CANCEL MY MAYDAY OF [time]. NO DISTRESS. POSITION [your position]. OUT." Do not switch off the radio — the coastguard will need to confirm the cancellation. Accidental alerts are common and not punished; failure to cancel one is, because it diverts rescue resources.

Is the SkipperCheck VHF SRC certificate accepted internationally?

Acceptance is decided by each country, charter company, insurer or radio authority — not by SkipperCheck. The certificate is aligned with CEPT/ERC/REC 31-04 and ITU Radio Regulations. National authorities including Switzerland (BAKOM), Denmark (Maritime Authority), Poland (UKE) and Germany (Wasserschutzpolizei) have confirmed in writing that they recognise it. Verify with your specific authority before purchase.