When a ship is in grave and imminent danger, the call is unmistakable. Mayday is the international radiotelephone distress signal, spoken three times, that indicates a vessel or aircraft requires immediate assistance.

The signal takes priority over all other traffic. It is followed by the vessel’s identity, position, nature of distress, and type of help needed. Coast radio stations and nearby ships are obliged to respond. False Mayday calls are serious offenses because they divert real rescue resources.

Crews practice distress communications in drills so that the format is automatic under stress. Digital selective calling and satellite systems now supplement voice Mayday, but the spoken word remains universally understood. Clear, calm Mayday procedure saves lives.

• International voice distress signal
• Indicates grave and imminent danger
• Takes absolute priority on the radio
• Must be followed by identity, position, and nature of distress