Flying After Diving

The waiting period before air travel after diving: DAN recommends at least 12 hours after a single no-deco dive and 18 hours after repetitive dives.

Flying after diving is risky because cabin pressure at altitude is significantly lower than at sea level, roughly equivalent to 1800 to 2400 m of elevation. Nitrogen still dissolved in your body after diving, harmless at surface pressure, can form bubbles when ambient pressure drops further, triggering decompression sickness in the air or after landing. The preflight surface interval exists to let that residual nitrogen wash out first.

The reference guidelines come from DAN: wait at least 12 hours after a single no-decompression dive, at least 18 hours after multiple dives per day or multiple days of diving, and substantially longer than 18 hours after dives requiring decompression stops. These are minimums, not guarantees, and many divers simply take a full 24 hours off before flying. Dive computers display a no-fly countdown after each dive based on their algorithm's view of your gas load.

The same logic applies to driving over high mountain passes after a dive trip, since altitude is altitude however you reach it. Plan the last diving day of a liveaboard or resort holiday accordingly: the final afternoon is for rinsing gear and packing, not for squeezing in one more dive before an evening flight. Your computer's no-fly timer is the minimum, not a target.