SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/scuba-dive-flag

What does the recreational "diver down" flag look like?

Red with a white diagonal stripe.

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  1. Red with a white diagonal stripe ✔
  2. Yellow with a black circle
  3. Green with a white cross

Why: The flag warns boats that divers are below. Boaters should slow down and keep clear. Some places require it by law, so learn your local rules.

Huh, didn't know that: The other recognized dive flag is the blue-and-white Alpha flag, used on boats whose movement is limited by divers.

The dad joke
That flag is red because it's embarrassed someone is diving under it without a snack.
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References

Answer: Red with a white diagonal stripe. The flag warns boats that divers are below. Boaters should slow down and keep clear. Some places require it by law, so learn your local rules.

  1. PADI: Dive Flag and Float www.padi.com/gear/flags
    Signal to boats that there are divers down below with a locally recognized red flag with a white diagonal stripe
    Checked 2026-10-12.
  2. NOAA: Guidance on the use of Warning Signals during Diving (2017) www.omao.noaa.gov/sites/default/files/documents/2017%20Warning%20Flag%20Guidance_Memo%20from%20RM%20to%20NDCSB_072717.pdf
    the red and white diver down flag and the international code flag Alpha
    Checked 2026-10-12.

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