Flying after diving: what DAN published, and who says something different.

Why it comes up at all

DAN's page on decompression illness states that decompression sickness symptoms usually appear within 15 minutes to 12 hours of surfacing, but that late onset, though rare, is possible, particularly when flying follows diving. DAN frames its answer in terms of cabin altitude, the altitude at which an airliner's pressurised cabin is held. For what decompression sickness is, see decompression sickness and barotrauma.

The 2002 DAN workshop recommendation

DAN held a one-day Flying After Recreational Diving Workshop in 2002. The proceedings were published as Flying After Diving Workshop, edited by R. D. Vann (Durham: Divers Alert Network, 2004), with the executive summary on pages 16 to 19. DAN publishes the workshop's consensus as follows.

The scope DAN states

• The guidance applies to air dives followed by flights at cabin altitudes of 2,000 to 8,000 feet (610 to 2,438 metres).
• It applies to divers who have no symptoms of decompression sickness.
• DAN states that the intervals reduce the risk of decompression sickness but do not guarantee avoiding it, and that longer surface intervals reduce the risk further.

What the guidance rests on

DAN's proceedings report chamber trials funded by DAN and run at Duke University from 1992 to 1999. In 802 trials with simulated flights at 8,000 feet, there were 40 cases of decompression sickness. DAN points out that the volunteers in those trials were dry and resting, so longer intervals may be needed for divers who were in the water and exercising, a question it said needed more study.

The proceedings also say that people flying while they already have symptoms are a bigger concern than symptoms that begin in flight. DAN treats that as an education issue: it states that divers with possible symptoms should get medical advice instead of flying. Any suspected decompression illness needs prompt medical care from a doctor.

DAN's current guideline page cites the same 2004 proceedings. It carries a PDF dated July 2020 but no publication date of its own.

The guidance it replaced

The first flying-after-diving workshop was sponsored by the Undersea and Hyperbaric Medical Society (UHMS) in 1989. The two DAN sources describe its advice slightly differently:

• DAN Europe (2009): 12 hours after as little as two hours of no-stop diving in a day, and 24 hours after several days of unlimited no-stop diving.
• DAN's 2004 proceedings: 12 hours after a single no-stop dive, 24 hours after repetitive diving over several days, and 48 hours after dives needing decompression stops.

DAN Europe adds that DAN had at one point suggested a simpler 24 hours after any diving, that the recreational diving industry objected, and that DAN revised its guidelines in 1991.

Where other bodies differ

PADI: 24 hours

PADI's blog post on things not to do right after diving, by Megan Denny (first published 18 July 2019, last updated 10 June 2024), gives a general recommendation of a 24-hour surface interval before flying after any type of diving. It also says to follow the dive computer's no-fly time, and to avoid other altitude exposure, such as mountain driving, ziplining and skydiving, for about 24 hours after diving.

The same post attributes to DAN a 24-hour wait after decompression dives. DAN's own pages do not give 24 hours for those dives: they say substantially longer than 18 hours and name no figure.

A TDI blog: several figures side by side

A TDI blog post by Jason Blair, an FAA pilot examiner, says it gives the author's own view and is not formal SDI or TDI policy. The post is undated. It lists figures from different bodies: DAN, 24 hours for repetitive dives; the US Air Force, 24 hours after any dive; and US Navy tables, about 2 hours. The 24-hour DAN figure there does not match DAN's current 18-hour guidance for repetitive diving, and appears to reflect older DAN advice.

The FAA: actual altitude, not cabin altitude

The US Federal Aviation Administration's Aeronautical Information Manual (section 8-1-2) is quoted by the TDI blog and by an AOPA article from December 2016. As they quote it, the FAA recommends:

• at least 12 hours before flying up to 8,000 feet above mean sea level after dives that did not need a controlled ascent;
• at least 24 hours after dives that did need one;
• at least 24 hours before any flight above 8,000 feet.

We could only check this wording through those two secondary sources, not on the FAA's own site. The key difference is the frame of reference. The FAA figures refer to the aircraft's actual altitude above sea level, while DAN's refer to the pressure altitude inside the cabin. The TDI blog notes that unpressurised light aircraft can fly higher than the cabin altitude of an airliner, which is why the two sets of figures are framed differently.

All the figures in one place

Each figure belongs to the body that publishes it. They differ in the diving they cover and in whether they mean cabin or actual altitude. For the practical side of taking gear on a plane, see travelling with dive gear.