After a spontaneous collapsed lung, scuba diving is a contraindication by default — but not always forever. The worry is not the dive itself; it is that a collapse can come back, and if it does at depth the trapped air expands as you surface and can become life-threatening. Current UK guidance opens a route back through definitive surgery, or five years clear, with a normal CT and lung function. Snorkelling and swimming are safe. Freediving is not the same as snorkelling. Dr Okiror is a consultant thoracic surgeon at London Bridge Hospital and The Lister Hospital Chelsea. Collapsed lung treatment page →
Last reviewed: July 2026 · Dr Lawrence Okiror FRCS(CTh) FRCSEd(CTh) · GMC 6150382
A default no after a spontaneous collapse — but UK guidance accepts a route back after bilateral pleurectomy, or five years clear, with normal CT and lung function
Safe. At the surface there is no meaningful pressure change, so the mechanism that makes scuba dangerous does not apply. Freediving to depth is not the same thing
Runs through a thoracic surgeon: a CT scan, lung function, and — where needed — a definitive operation. Occupational diving is held to a higher standard again
A pneumothorax — the medical term for a collapsed lung — happens when air escapes into the space around the lung and stops it expanding fully. If it happened once without an obvious cause, it is called a spontaneous pneumothorax, and the single most important fact about it is that it can happen again.
That is what makes scuba the problem, not the water itself. A diver breathing from a tank takes in air at the pressure of the depth they are at, and as they rise that air expands and must be breathed out. If a lung collapses at depth, the air trapped in the chest expands the same way as the diver ascends — and because it has nowhere to go, it can build into a tension pneumothorax that presses on the heart and the other lung.
On land that is an emergency; at depth it is extremely difficult to treat, which is why diving-medicine committees take a history of spontaneous collapse so seriously. So the honest default answer to “can I scuba dive again?” is no, until proven otherwise — but for many people, it can be proven otherwise.
“Until proven otherwise” is doing real work in that sentence. There are two recognised routes back to recreational diving — set out below.
The current UK standard is set by the UK Diving Medical Committee, whose pneumothorax guidance was last reviewed in October 2023. It is more nuanced — and more workable — than the blanket bans you may read online. It accepts that in someone with a history of spontaneous collapse the risk can fall back close to that of the general population in two situations.
Both routes carry the same non-negotiable condition: a CT scan of the chest and lung function tests must show no significant residual lung disease — no bullae, blebs or other weak points that could rupture under pressure. The CT matters because these can be invisible on an ordinary chest X-ray.
A collapse caused by an injury — a fall, an accident, rib fractures — is viewed more leniently, because there is a clear reason it happened and no reason to expect recurrence once the chest has fully healed with normal imaging and lung function.
One realistic caveat: being cleared by a UK medical referee is not the same as a dive operator abroad, or a travel insurer, agreeing to take you on. Reputable operators are cautious, so it is worth confirming both the medical clearance and the practical acceptance before committing to a trip.
If you have been told diving is permanently off the table without a scan or lung function, a specialist review can establish whether a route back applies to you.
Request a second opinion →If scuba is off the table for now, it is easy to assume anything in the water is. It is not. Snorkelling at the surface and swimming are considered safe after a collapsed lung. When you snorkel at the surface you are breathing ordinary air through a tube with your face in the water, at essentially the same pressure as standing on the beach. There is no compressed gas and no meaningful change in pressure — so the mechanism that makes scuba dangerous, air trapped in the chest expanding as you rise from depth, simply does not arise.
That is the reassuring part, and for most people it means the sea is not closed to them at all. The one thing that matters is what “snorkelling” is allowed to mean.
This is the point most often got wrong, including in online discussions where someone is told snorkelling is fine and then reasonably asks “so how deep can I freedive in a pool?” The two are not the same activity, and the difference is exactly the thing that matters.
The gas source is not what makes diving risky — the change in pressure is. When you breath-hold dive down to depth and come back up, any air trapped in the chest expands on the way up in proportion to how deep you went, in exactly the same way as it would on scuba. It does not matter that the air came from your own lungs rather than a tank. If a collapse develops at depth on a breath-hold, the same dangerous expansion happens on ascent.
On top of that, lung barotrauma has been reported after breath-hold dives in people with no tank at all, thought to be due to uneven expansion of parts of the lung. And a freedive in a deep pool is not shallow — the deep freediving pools people ask about run to 20–25 metres. This is why the internationally used recreational diver medical now screens freediving under the same rules as scuba, not alongside snorkelling.
The practical rule is simple. Staying at the surface is snorkelling, and it is fine. Going down to depth on a breath-hold is freediving, and it should be assessed the same way as scuba — not waved through because no tank is involved.
If you dive for a living — as an instructor, a commercial diver, or in the forces — the bar is higher than for a recreational diver, and it is set by a different system. It helps to keep three regimes separate, because they are often blurred together.
Recreational diving. New divers complete a diver medical questionnaire before a course. A collapsed lung or chest surgery is one of the items that stops the self-declaration and sends you to a doctor for clearance against the standard above. There is no “PADI test” that clears a pneumothorax; the training agency simply requires the medical sign-off.
Professional divers and instructors. Anyone diving at work in the UK falls under the Diving at Work Regulations 1997 and must hold a current Certificate of Fitness to Dive from an HSE Approved Medical Examiner of Divers, renewed annually. For this bar, the realistic route back after a spontaneous collapse is a definitive bilateral pleurectomy with normal CT and lung function.
Military diving. Stricter again: a history of spontaneous pneumothorax is generally treated as disqualifying for the diver branch, surgery notwithstanding, subject at best to individual review. Merchant seafarers who dive as part of their work are assessed under the commercial (HSE) route.
Bilateral pleurectomy has a failure rate under 1%. Keyhole talc or abrasion pleurodesis alone (5–10% recurrence) is not regarded as sufficient for someone intending to dive.
Pneumothorax surgery →The advice on this page follows the current UK diving-medicine position rather than the oldest blanket bans. The UK Diving Medical Committee guidance on pneumothorax (reviewed October 2023) sets out the two routes back to recreational diving — bilateral pleurectomy, or five years clear if unoperated — each conditional on a normal chest CT and lung function.
The British Thoracic Society guideline on respiratory aspects of fitness for diving (Thorax, 2003) remains the detailed thoracic reference, and is the source of the position that surgical pleurectomy — not keyhole pleurodesis alone — is the appropriate operation for someone intending to dive. Occupational standards are set separately: professional and instructor diving falls under the Diving at Work Regulations 1997, requiring an HSE Approved Medical Examiner of Divers certificate; military diving is assessed under its own stricter standards.
GPs and referring clinicians may prefer the companion fitness to dive after pneumothorax clinical reference, which sets out the UKDMC, BTS, HSE and military standards side by side with the referral workup.
This page is general information, not a substitute for advice about your own situation. Guidance changes over time, and whether you are fit to dive depends on your CT, your lung function, and the reason your lung collapsed. If you develop new breathlessness or chest pain, seek urgent medical assessment.
Common questions from patients and divers after a pneumothorax. For treatment of the collapse itself, and when surgery is recommended, see the collapsed lung treatment page →
Book a Consultation →Or call Jo Mitchelson:
020 7952 2882
Appointments within 2–3 days. Self-referrals welcome. Consultations at London Bridge Hospital and Lister Hospital Chelsea, with review of your CT and lung function to advise whether — and how — a return to diving is possible.
Jo Mitchelson, PA · 020 7952 2882 · pa@lungsurgeon.co.uk
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Diagnosis and keyhole surgery for pneumothorax, and when an operation is recommended to prevent recurrence
Fitness to Dive After Pneumothorax — Clinical ReferenceThe UKDMC, BTS, HSE and military standards side by side, with the referral workup. For GPs and specialists
Flying After a Collapsed LungWhen it is safe to fly after a pneumothorax — full re-inflation confirmed on X-ray, then a further seven days