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SESK: Stuff Everyone Should Know · sesk.info/scuba-biggest-pressure-change-shallow

Where is the risk of pressure injuries (barotrauma) greatest for divers?

In shallow water, from the surface to about 33 feet.

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  1. From the surface to about 33 feet ✔
  2. Between 90 and 130 feet
  3. Only below 130 feet

Why: Pressure doubles in the first 33 feet, the biggest change of any stretch of the dive. So ears, sinuses, masks and lungs face their toughest squeeze close to the surface.

Huh, didn't know that: That is also why the last part of an ascent, near the surface, is the part to take slowest.

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Why do scuba divers fall backwards off the boat? Because if they fell forwards, they'd still be in the boat.
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References

Answer: From the surface to about 33 feet. Pressure doubles in the first 33 feet, the biggest change of any stretch of the dive. So ears, sinuses, masks and lungs face their toughest squeeze close to the surface.

  1. DAN: Recognizing and Preventing Barotrauma dan.org/safety-prevention/diver-safety/divers-blog/recognizing-and-preventing-barotrauma
    The risks associated with all these types of barotrauma are greatest at shallow depths (from the surface to about 33 feet).
    Checked 2026-10-12.

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