Freediving safety & shallow water blackout
The most common question we get is "is freediving dangerous?" The honest answer: solo freediving is dangerous — every freediving fatality is, essentially, a variation of someone blacking out alone. Trained freediving with a buddy and the right protocols is a low-incident sport.
What shallow water blackout is
As you descend, ambient pressure compresses your lungs and the partial pressure of oxygen rises — that's why you feel "fine" deep down even on low oxygen. On the ascent, as pressure releases, that partial pressure drops fast. If you cut it too close, oxygen falls below the threshold to keep you conscious — usually in the last 5 metres or at the surface.
You don't feel it coming. There's no gasp, no warning. That's why the rule is absolute: never freedive alone, ever.
The buddy system, properly done
"Having someone with you" is not the buddy system. The real protocol — taught on AIDA 2 onwards — is:
- ·One diver descends, one watches from the surface — never both at once.
- ·The surface buddy descends to meet the diver at roughly 10 metres on ascent.
- ·Both surface together. Buddy monitors the diver for the first 30 seconds — the highest-risk window.
- ·If anything is off (samba, blackout), buddy is trained to respond immediately.
Things that increase risk
- ·Hyperventilation before a dive. Doesn't add oxygen — just delays the urge to breathe past safe limits.
- ·Pushing personal bests without a coach. Most blackouts happen on max-effort dives.
- ·Short surface intervals. CO2 and oxygen need time to reset between dives.
- ·Freediving after scuba — increases DCS risk; AIDA covers the wait times.
What a course actually trains
On AIDA 2 you'll practise a real rescue on an unconscious-victim drill — surface tap, blow-talk-blow, and tow. It feels uncomfortable to roleplay. That discomfort is the point: when something happens, the motor pattern is already there. See our full safety page for the protocols we run on every session.
Safety — common questions
Is freediving dangerous?
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Solo freediving is high-risk — essentially all fatalities involve someone diving alone or without a trained buddy on the surface. Trained, supervised freediving with proper buddy protocols is statistically a low-incident sport.
What is shallow water blackout?
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A loss of consciousness in the last few metres of ascent or at the surface, caused by oxygen partial pressure dropping rapidly as ambient pressure releases. The diver feels fine right up until they don't — it's painless and silent. That's why a trained buddy is non-negotiable.
Can you get decompression sickness from freediving?
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Rare in recreational freediving but possible with repetitive deep dives and short surface intervals — and after scuba diving. AIDA training covers safe surface-interval rules and the no-fly / no-scuba rules around freediving.
What's the buddy system?
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One person dives, one person watches from the surface, ready to assist. The watching buddy meets the diver at depth on the ascent, escorts them up, monitors the first 30 seconds at the surface (the highest-risk window), and is trained to perform a rescue if needed.
Learn the protocols, not just the depth.
Every AIDA course we run starts and ends with safety. Message us to book.
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