What is the international distress signal for someone requiring urgent help?

The international distress signal for someone requiring urgent help involves waving arms above the head. This method is universally recognized as a signal indicating that someone is in trouble and needs immediate assistance. It serves as a clear visual cue that can be seen from a distance, making it effective for attracting the attention of nearby vessels or individuals.

While holding a flare is another method to signal for help, it typically requires specific conditions and is used primarily in situations where visibility is limited or when there is a need to signal over a distance. Using a loudspeaker could make noise but would not be effective in signaling visually to those who are not close by. Blowing a whistle may attract attention but lacks the visibility and recognition that comes with the clear, unmistakable gesture of waving arms above the head. Thus, the action of waving arms is the most recognized and universally understood form of signaling for assistance.