Why flying matters
After a dive your body still holds extra nitrogen, which it releases slowly over many hours. Airliner cabins are pressurised, but only to the equivalent of being on a mountain about 1,800 to 2,400 metres (6,000 to 8,000 feet) high. That drop in pressure is like ascending a little further at the end of your dive. If you still carry a lot of nitrogen, the lower pressure can let it form bubbles and cause decompression sickness, sometimes during the flight itself.
The widely used guidelines
The most widely quoted guidance comes from a workshop held by Divers Alert Network (DAN) in 2002. It recommends minimum surface intervals before flying in an airliner:
| Diving you have done | Minimum wait before flying |
|---|---|
| A single no-decompression dive | 12 hours |
| Several dives in a day, or several days of diving | 18 hours |
| Dives that needed decompression stops | Substantially longer than 18 hours |
These are minimums, not guarantees. Many divers and operators simply plan a full 24 hours between the last dive and the flight, which is simple to remember and adds a margin. Your dive computer may show its own no-fly time; follow whichever is longer.
Plan your trip around it
The easiest way to stay safe is to make the last day of a dive trip a dry day. Use it for a land tour, snorkelling or packing. If you do make a last dive, keep it shallow and well inside your no-decompression limits.
Altitude on the ground
Flying isn't the only way to reach altitude. Driving over a mountain pass after diving has the same effect, and so does a scenic flight in a small, unpressurised aircraft, which can climb higher than an airliner's cabin pressure. Diving in a lake at altitude also needs special planning, as the surface pressure is already lower than at sea level.
Flying before diving
Flying before diving is not a problem for decompression. Long flights can leave you dehydrated and tired, though, so drink water, rest and give yourself an easy first dive.
If you have symptoms
If you feel joint pain, numbness, tingling, unusual tiredness or any other possible symptom of decompression sickness after diving, don't board a flight. Get medical help, breathe oxygen if it's available and contact a dive emergency hotline. Symptoms that start during a flight need medical attention as soon as you land, and the crew should be told.
Frequently asked questions
How long should I wait to fly after scuba diving?
At least 12 hours after a single no-decompression dive, and at least 18 hours after several dives or several days of diving. Many divers wait 24 hours.
Is snorkelling before a flight OK?
Yes. Snorkelling at the surface doesn't load you with nitrogen, so there is no waiting time.
Does breathing nitrox let me fly sooner?
Not by the general guidelines, which don't change with the gas. Some computers calculate no-fly time from your actual nitrogen loading, but follow at least the minimum intervals.