A Mayday call opens with the word MAYDAY itself, spoken three times, then THIS IS and your vessel's name, also three times, then your call sign or MMSI (your radio's own ID number) once if you carry either. Repeat MAYDAY and your vessel's name a final time, and the real message begins: give your position first, since it's the single most essential fact a rescue effort needs, then what's wrong, the help you need, how many people are aboard, and anything else useful, closing with OVER. On a DSC-equipped set, press and hold the red distress button before you speak — it sends your MMSI, your position only if the set has working GPS data, and a broad distress category if one was selected — then make the spoken call anyway, since the button cannot send the full situation.
A Mayday call sounds intimidating mostly because nobody rehearses it: you hope to never key the mic for this reason, so the words never get the chance to become familiar the way an everyday hail does. But the call itself is short, and it follows one fixed shape everywhere — not for ceremony, but because that shape is what lets a stranger, hearing you for the first time, act on what you say. Once you know the order and why each piece exists, there's nothing left to freeze up over: you're working through a short, logical list, not composing a speech. This guide covers when the call is actually warranted, exactly what to say and in what order, and how the DSC button fits in before you ever speak a word.
When It's Actually a Mayday
MAYDAY is reserved for grave danger to your vessel or the people aboard it — fire, sinking, a holed or badly flooding hull, a serious injury. It isn't the right call for a problem that leaves you and your crew safe, and it isn't the right call for a problem that's genuinely urgent without being immediately dangerous, either — a boat drifting toward shore or into a busy channel, for instance. Situations like that use a different distress signal with a lower threshold — a separate call this course covers on its own. The test worth keeping in mind isn't how worried you feel; it's whether the danger is real, immediate, and serious enough that you need help now, not eventually. Get that judgment right, and everything downstream — who answers, how fast, and with what — follows from it.
Open With MAYDAY, Your Boat, and Your ID
Every Mayday opens the same way, and the repetition is doing real work, not padding: on a noisy channel, through static or crosstalk, three chances to catch a single word beat one. Start by speaking the word MAYDAY itself three times. Follow it with THIS IS, then your own vessel's name, also three times — the boat's identity matters as much as the fact that something is wrong. If you carry a call sign or an MMSI, add it once; if you carry neither, move on. Then say MAYDAY and your vessel's name one more time — a short pause that marks the shift from announcing the emergency to actually describing it. Nothing in this opening states what's wrong yet; its whole job is making sure whoever is listening knows, beyond doubt, that a distress call is starting, and which boat is making it.
Give the Facts in the Order a Rescuer Needs Them
Once the opening ends, say your position — as latitude and longitude if you have it, or as a bearing and distance from a landmark you can identify. Position earns that priority because a rescue effort treats it as the single most essential fact in the whole message, ahead even of what's actually wrong. After position: what's actually wrong — fire, flooding, a serious injury — then the help you want, how many people are aboard, and any other detail that could matter, like the vessel's length or an unusual feature of its hull. Close with the word OVER, let go of the button, and listen. No answer? Stay on full power and repeat the whole call from the top rather than assuming you weren't heard.
Press the DSC Button First, Then Talk
If your radio has DSC, lift the guard over the red distress button and hold it down until the set confirms transmission — IMO guidance says more than three seconds, while training examples commonly use about five, so know your own radio's instructions. That press sends an automatic alert carrying your boat's MMSI, and — only when your set has working GPS data — your position. If you selected a nature of distress first, the alert can carry that broad category too; otherwise it is sent as undesignated. Either way, the button is a head start, not the whole job: follow it immediately with the spoken Mayday call above, because the alert cannot describe the full situation, what help you need, or how many people are aboard. Pressed it by accident? Cancel it right away through your set's own menu — never by switching the radio off, since most sets simply resume the alert once they're powered back on — then confirm the cancellation by voice, with your MMSI and boat name, on channel 16.
None of this needs to live in your memory perfectly before it matters — a Mayday call is short enough, and logical enough, that most of it falls into place once you understand why the order is what it is: position first because it's the fact a rescue effort treats as most essential, the DSC button first because it buys everyone a head start while you're still talking. What's worth doing now, long before any emergency, is finding your own radio's distress button, checking whether it's wired to a GPS, and saying the opening out loud once so it isn't the first time your voice has ever done it. SailStarter's Module 9 lessons walk through this alongside the rest of marine radio communication — channel 16, hailing, and the everyday habits that make a VHF set feel familiar — so the one call you hope never to make is one you'd actually know how to.