Technical Diving

The Deepest Scuba Dive Ever

Ahmed Gabr touched 332.35 m in 2014 after a 12 minute descent and spent nearly 14 hours coming back. The full story of scuba's depth records, and the wall physics builds at 300 m.

By Mat Mora · Updated 11 July 2026 · ~9 min read

Depth records are the part of technical diving everyone can feel. The numbers are simple, the stakes are obvious, and the physics is merciless. This is the story of how divers clawed from 100 m to 332 m over four decades, what a record dive actually involves, and why the graph has gone flat since 2014.

The record: Ahmed Gabr, 332.35 m

On 18 September 2014, Egyptian technical diving instructor and former army officer Ahmed Gabr left the surface at Dahab on the Red Sea, following a weighted line into open blue water. Around twelve minutes later he collected a tag at 332.35 m, a depth where the pressure is over 34 times what your body feels reading this, and where his leanest bottom mix was so short on oxygen it would have knocked him unconscious if breathed at the surface. Then he began the real dive: close to 14 hours of decompression, creeping up the line stop by stop while a support team rotated down to him with fresh cylinders, food and slates. The operation involved years of preparation, a team of dozens, and more than 60 cylinders of nine different gas mixes. Guinness verified the depth from tagged line measurements and pressure loggers.

The shape of that dive tells you everything about extreme depth: the record is not the going down, it is the coming back. Twelve minutes of descent wrote a decompression debt of nearly 14 hours. Every extra metre would have written more.

How the record got there

The deep-air era peaked in the early 1990s around 155 m, at the very edge of what nitrogen narcosis and gas density allow a human to survive, and it killed many of the divers who pushed it. Helium changed the game. Trimix (oxygen, helium, nitrogen) kept divers clear-headed and their gas breathable at depths where air is closer to syrup than to atmosphere.

The women's records tell the same story on a parallel track: Verna van Schaik's 221 m at Boesmansgat in 2004 stood for years before Karen van den Oever pushed the mark past 240 m at the same cave in the 2020s. And Boesmansgat itself, a remote sinkhole in the South African Kalahari, keeps appearing in this story for a reason: a deep, still, private hole in the ground is the closest thing depth records have to a laboratory. It is also where one of diving's most haunting tragedies unfolded, which we tell in the dives that rewrote the rules.

What it actually takes

A 300 m attempt is an expedition wearing a wetsuit. The diver is almost the smallest part of it:

• Gas logistics. No one carries a dive like this. The diver descends with a handful of cylinders; everything else, dozens of tanks of precisely blended mixes, is staged along the line and ferried by support divers who each need their own decompression plan.
• A gas for every zone. Travel mixes for the descent, an extremely hypoxic trimix for the bottom, then a ladder of intermediate trimixes, nitrox and finally pure oxygen on the way up. Breathe any of them at the wrong depth and it can kill: the bottom mix causes blackout near the surface, the deco gases convulse at depth.
• A support pyramid. Deep support divers who meet the record holder at 100 m and below, mid and shallow teams rotating for hours, surface crews, medics, a recompression chamber on standby.
• Years of progression. Record holders build depth over dozens of progressively deeper dives, testing how their bodies tolerate helium tremors, compression and cold. This progression is precisely what the fatal attempts skipped.

Why 350 m may never happen on scuba

Since 2014 the record has not moved, and the reasons are physics rather than courage:

• Gas density. Breathing resistance rises with pressure until the work of breathing itself generates more CO₂ than you can exhale, a spiral that ends in blackout. Research presented by Gavin Anthony and Simon Mitchell puts the hard ceiling around 6.2 g/L. At 330 m, even a mix that is nearly all helium sits beyond it. Every open-circuit diver at that depth is past the physiological red line just by breathing.
• HPNS. Below roughly 180 m, helium under compression irritates the nervous system: tremors, jerks, cognitive fog. Slower descents help, but a scuba descent cannot be slow, because every minute deep adds hours shallow.
• The decompression wall. The deco debt grows brutally with depth. Gabr's 12 minutes of travel cost 14 hours. A 350 m touch would demand a schedule at the edge of what a human body can physically endure in the water: cold, dehydration, oxygen exposure and all.
• No model has been there. Decompression algorithms are validated on data from far shallower diving. At 300 m they are extrapolations. The record dives that succeeded adjusted published models with private experience and luck, and the ones that failed found the edges. We unpack this in how decompression planning works.

Want to feel these limits instead of reading about them? The deco planner in the Diving Standard app has a perspective mode that runs to 300 m. Plan a 10 minute bounce to record depth and watch the schedule pass 13 hours, the gas plan pass 40 cylinders, and the warnings explain exactly which human limit you crossed first. It is the fastest way to understand why this record stands.

The deepest dives that were never records

This story has a dark twin. For every verified record there were attempts that ended in silence: divers who touched depths no one can confirm and did not live to log them. The community's accident reports from those dives, more than the records themselves, are what built modern deep diving protocol. That is the subject of the next article in this series, and if you only read one of the two, read that one.