Flying after diving: how long you actually have to wait

If you are reading this on the last morning of a dive trip with a boarding pass in the other hand, you want a number. It is below, with the name of the body that published it, because on this subject who said it matters as much as what they said.

Two questions get asked here and they are not the same question. Flying after diving has published intervals attached to it and a real mechanism underneath. Diving after flying has neither, and the honest answer to it is not a shorter wait but no published wait at all. This page answers both, in that order.

Which of these are you?

Four situations. Find yours and you can stop reading.

• One dive yesterday, no decompression stops. DAN’s minimum is 12 hours from surfacing.¹
• Two or three dives in one day. DAN’s minimum is 18 hours.¹ The count is dives, not days — a two-tank morning puts you here.
• Several days of diving, then a flight. Also 18 hours under DAN’s guideline.¹ This is the most common recreational case and the one people most often get wrong by reaching for 12.
• Anything with a compulsory decompression stop, or trimix or heliox. DAN declines to name an interval and says substantially longer than 18 hours appears prudent.¹ PADI’s guidance does name one — at least 24 hours.² Twenty-four satisfies both, which is why most operators plan around it.

One more that catches people out: the interval runs from the moment you surfaced, not from the moment you got back to the hotel. Climb out at 16:20 and a 12-hour interval is 04:20, an 18-hour interval 10:20 the next morning.

Why the number is what it is

Underwater, the nitrogen in the air you breathe dissolves into your tissues in proportion to how deep you went and how long you stayed. Surfacing lets it come back out, slowly, over hours — which is what a surface interval is for. A commercial aircraft cabin is not sea level: PADI puts the equivalent altitude at 6,000 to 8,000 feet, or 1,800 to 2,400 meters.² Climbing into that while you are still carrying a load drops the pressure again, and gas that was staying quietly in solution can come out of it as bubbles.

The 12 and the 18 are not physical constants. They came out of trials run at Duke between 1992 and 1999 on profiles near recreational no-decompression limits. In single no-stop dives to 60 feet or deeper, no decompression sickness occurred at surface intervals of 11 hours or longer; in repetitive no-stop dives, it occurred at intervals below 17 hours.³ The 2002 workshop took those thresholds and rounded up.

That explains a number you may have seen. Seventeen hours is quoted in a great many places, including an older version of this page, and it is the experimental threshold rather than the recommendation. The published figure is 18.¹

Where the authorities disagree — and they do

Most pages on this subject give one set of numbers and imply the world agrees. A review hosted by the US National Library of Medicine says otherwise in terms: “there is little consensus among experts and guidelines,” noting the US Navy at a two-hour interval and the US Air Force and DAN at 24 hours.³

Authority	Single no-stop dive	Repetitive or multi-day	Decompression dive
DAN, 2002 workshop consensus1	12 hours	18 hours	“substantially longer than 18 hours” — no figure given
PADI2	at least 12 hours	at least 18 hours	at least 24 hours
US Air Force, per an NIH review3	24 hours	24 hours	24 hours
US Navy, Table 9-64	computed from your repetitive group and the altitude gained	same method	exceptional exposure: wait 48 hours

The last row needs care. The US Navy does not publish a flat interval at all: its table is indexed by the diver’s repetitive group and by how much altitude is being gained, and for many light profiles it returns 0:00 even for an ascent to 8,000 feet — while for a heavily loaded diver in group Z it returns 21:01, and after an exceptional exposure dive it says wait 48 hours.⁴ The manual instructs you to use the highest repetitive group reached in the previous 24 hours, and to treat a commercial flight as a final altitude of 8,000 feet.⁴

Read that table as a permission slip and you will get hurt. It governs a medically screened military population, diving to a schedule, usually with a chamber within reach, at an accepted level of risk that is not yours on a holiday. The recreational world teaches DAN’s numbers, and DAN’s numbers are the ones to use. The spread is useful for a different reason: it tells you 12 and 18 are a consensus with a margin built in, not a cliff edge at hour 11.

It is altitude, not aeroplanes

The aircraft is incidental — what matters is the pressure drop, and there is more than one way to arrange one. The US Navy’s table is titled “Required Surface Interval Before Ascent to Altitude After Diving” — ascent, by any means — and its columns run from 1,000 to 10,000 feet of altitude gained.⁴ PADI is blunter for a general reader: avoid mountain climbing in the first 24 hours after a dive, and if you are combining climbing and diving on one trip, do the climbing first.²

In practice this catches divers out in three places.

• The drive home over a pass. Central America and the Caribbean are full of sea-level dive sites with high ground between them and the airport — Costa Rica’s Pacific coast to San José, or the road inland from much of Honduras’ coast. If the road climbs, it counts.
• The excursion on the last day. Ziplines, cable cars, volcano tours and hilltop viewpoints are sold hard at exactly the moment a diver has a no-fly interval running. Check the altitude before booking.
• Landing somewhere high. The NIH review notes that below 610 meters a flight’s effect is “considered mild enough not to warrant special consideration”³ — which is why an airport in the mountains is a different proposition from one on the coast.

One case is counter-intuitive, and the US Navy states it plainly: if the dive site is already at or above 8,000 feet, no surface interval is required before a commercial flight, because taking off from there increases the pressure around you rather than reducing it.⁴

What your dive computer’s no-fly timer is

Most computers show a no-fly countdown and a lot of divers treat it as the answer. It is one manufacturer’s decompression model applied to the dives that one computer recorded, with that manufacturer’s assumptions about cabin altitude and its own margin. Different makes give different answers on the same profile, none is the published guideline, and none knows about the dives you did before you switched it on.

So: use the same computer all week, because a fresh one starts from a clean tissue load it has no right to assume. If you rented it, work from DAN’s intervals, because the log goes back to the shop with the unit. And where the timer and the guideline disagree, take the longer — a timer reaching zero says this model’s constraint has been satisfied, not that flying is now safe.

Diving after flying — the other direction, and the different answer

This page has lived at a URL named for the reverse question since 2021, and it deserves a straight answer rather than a mirror image of the one above.

No diving agency publishes a required interval between landing and your first dive. That is not an oversight. Flying does not load you with inert gas — it does the opposite. A flight sits you at reduced pressure for a few hours, leaving you with slightly less dissolved nitrogen than you would have had at home, so there is nothing to discharge before you get in the water. The direction that has a rule is the direction where pressure falls, and this is not it.

What limits you is your condition, and it is not trivial. A long-haul flight leaves most people tired, dehydrated and, if you have crossed time zones, out of step with the clock the boat runs on. None of that is a decompression obligation and all of it makes a first dive worse. The planning is unglamorous: drink water on the aircraft and after it, sleep before the first dive, and make it an easy one whatever the schedule says.

The exception is the one above. If you land at altitude, or drive up from the airport, you have made an ascent and the rules in the other direction attach to it. Diving a mountain lake on arrival is altitude diving, a different subject with its own tables and its own training.

When the rule is already broken

Nobody writes this section because everybody writing about it is selling a dive. So, plainly.

If you have symptoms, do not get on the aircraft. DAN’s guidance is that divers should seek medical advice and avoid flying if they notice signs or symptoms that may indicate decompression sickness,⁵ and the workshop’s own summary puts it as a teaching point: divers “need to be taught to seek medical advice rather than to fly if they note signs and symptoms consistent with decompression illness.”⁶ Joint pain, unusual fatigue, a rash or mottled skin, tingling or numbness, dizziness, difficulty thinking clearly. Boarding takes you to a lower pressure, away from a chamber, and out of contact for hours — three ways of making one situation worse.

Get those symptoms in front of someone who can read them. DAN runs a 24-hour emergency line on +1-919-684-9111 that will speak to you or to a local physician, and it will know where the nearest chamber is.⁷ Ringing it commits you to nothing.

If you have no symptoms but not enough hours, there is no published shortcut. What is within your control is the rest of the margin: move the flight before you have already missed it, and treat DAN’s interval as the minimum it is described as rather than a target to shave.

Plan the last day and the question never comes up

Almost every version of this problem is created a week earlier, by booking a flight before booking the diving.

Count backwards from the flight rather than forwards from the last dive. A 14:40 departure with an 18-hour interval means the last dive has to surface by 20:40 the previous evening, so an afternoon flight leaves the day before it intact. Move that departure to 07:00 and the deadline goes back to 13:00 two days out, which takes most of the day before the flight with it. Either way the day you fly is not a diving day, and a week’s holiday buys five or six diving days rather than seven.

If the schedule is already fixed, tell the shop your flight time on the first morning rather than the last: a good operator will plan the week around it and refuse you a dive that does not fit. And if you do dive on the final day, make it the lightest of the trip — one shallow no-decompression dive puts you in the 12-hour band instead of the 18.

Where to next

• Whether to start at all, and what it costs: how much scuba diving costs
• Your first dive, and what actually happens on it: how to prepare for scuba diving
• Medical fitness to dive, and what the dive-shop questionnaire asks: scuba diving with asthma
• Deciding between the two: snorkeling versus scuba diving
• Gas mixes, and what nitrox does and does not change: nitrox scuba diving

Frequently asked questions

How long after scuba diving can you fly?+

The guideline most of the recreational diving world teaches comes from the 2002 Flying After Recreational Diving Workshop, and the Divers Alert Network publishes it as follows: a minimum preflight surface interval of 12 hours after a single no-decompression dive, and 18 hours after multiple dives in a day or multiple days of diving (DAN). DAN's own wording is that these recommendations should reduce the risk of decompression sickness but do not guarantee avoidance of it.

Is it 17 hours or 18 hours after repetitive dives?+

Eighteen. Seventeen is a real number from the research behind the guideline rather than the guideline itself: in the trials run at Duke between 1992 and 1999, decompression sickness occurred in repetitive no-stop dives at surface intervals below 17 hours (StatPearls, NCBI Bookshelf). The 2002 workshop rounded up to 18 to put a margin on it, and 18 is what DAN publishes. If you have seen 17 hours quoted somewhere — including on an older version of this page — that is where it came from.

How long should you wait after a decompression dive?+

The agencies part company here, and it is worth knowing rather than being handed a single figure. DAN declines to name a number, saying only that a preflight surface interval substantially longer than 18 hours appears prudent, because the workshop recorded little experimental evidence for decompression dives (DAN). PADI's consumer guidance does name one, at least 24 hours (PADI). Twenty-four hours satisfies both.

Does driving over a mountain count as flying after diving?+

It is the same problem, because what matters is the drop in pressure rather than the aircraft. The US Navy's table on this is titled for ascent to altitude after diving rather than for flying, and it treats a commercial cabin as a nominal 8,000 feet for the purpose of computing the interval (US Navy Diving Manual, Revision 7, Table 9-6). PADI advises avoiding mountain climbing in the first 24 hours after a dive, and suggests doing the mountain first if you are combining the two on one trip (PADI).

How long after flying can you scuba dive?+

No diving agency publishes a required interval, and the reason is that the pressure change runs the other way. A flight leaves you with less dissolved inert gas than staying at sea level would, so there is nothing to discharge before you get in the water. What limits you is your condition rather than the clock — fatigue, dehydration and jet lag after a long flight are all worth taking seriously before a first dive, and the exception is landing somewhere high, or driving up from the airport, which is an ascent to altitude and follows the rules in the other direction.

Can I trust my dive computer's no-fly timer?+

Use it as a prompt, not as an authority. A no-fly countdown is one manufacturer's decompression model applied to the dives that particular computer recorded, and different makers make different assumptions about cabin altitude and about how much margin to leave. It also knows nothing about the dives you did on a rented computer earlier in the week. When the timer and the published guideline disagree, take whichever is longer, and if you rented the computer, work from the guideline, because you lose the dive log when you hand it back.

What should I do if I get decompression sickness symptoms before a flight?+

Do not board. DAN's guidance to divers is to seek medical advice rather than to fly if they notice signs or symptoms consistent with decompression illness (DAN Southern Africa). Getting on the aircraft takes you to a lower pressure, away from a chamber, and out of reach of help for several hours. DAN operates a 24-hour emergency line on +1-919-684-9111 that will talk to you or to a local doctor (DAN emergency assistance). That call is how you find out whether what you are feeling is decompression sickness.

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References

Footnotes

1. “Flying After Diving.” Divers Alert Network, dan.org. The recommendations are the consensus reached by attendees at the 2002 Flying After Recreational Diving Workshop. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰

2. “10 Things You Should Never Do Immediately After Diving.” PADI Blog, blog.padi.com. ↩ ↩² ↩³ ↩⁴

3. Strauss, Michael B., et al. “Flying After Diving.” StatPearls, NCBI Bookshelf, National Library of Medicine, ncbi.nlm.nih.gov. ↩ ↩² ↩³ ↩⁴

4. U.S. Navy Diving Manual, Revision 7, Volume 2. Table 9-6, “Required Surface Interval Before Ascent to Altitude After Diving”, with Notes 1–5, divetable.info. ↩ ↩² ↩³ ↩⁴ ↩⁵

5. “Flying After Diving.” DAN Southern Africa, 15 April 2021, dansa.org. ↩

6. Vann, R. D., ed. Flying After Recreational Diving Workshop Proceedings, executive summary. Divers Alert Network, Durham, North Carolina, 2004. ISBN 0-9673066-4-7. Summarized at dan.org. ↩

7. “Emergency Assistance.” Divers Alert Network, dan.org. ↩