What is a recommended method for signaling distress underwater?

Employing visible hand signals, sounds, or lights is the recommended method for signaling distress underwater because these methods are immediately recognizable and can effectively communicate your situation to other divers or surface support. Hand signals are widely understood in the diving community, such as the "OK" or "emergency" signals, making them a reliable choice. While audible signals (like tapping on your tank) and the use of underwater lights can draw attention, they provide a means to indicate urgency in a situation where verbal communication is not possible.

Using a dive flag exclusively does not convey distress effectively to other divers who may not see the flag or understand its context. Writing messages in the sand can be impractical and time-consuming, especially underwater where conditions may be less than ideal. Blowing bubbles rapidly is not a recognized distress signal and may not communicate the intended message clearly. Therefore, the combination of visual, audible, and light signals serves as a robust way to catch the attention of other divers or rescuers and communicate a need for assistance.