What is nitrox diving?
Updated 2026-06-30 · Certification
Nitrox — also called enriched air or EANx — is breathing gas with more oxygen and less nitrogen than normal air (which is about 21% oxygen; common nitrox blends are 32% or 36%). Because you breathe in less nitrogen, your body on-gasses more slowly, which extends your no-decompression limits and can mean longer dives or shorter surface intervals.
The trade-off: the extra oxygen creates its own shallower maximum depth, so nitrox isn't for going deeper — it's for staying longer at recreational depths. It needs a short specialty course, usually a single day of theory.
The benefit: more bottom time
Nitrogen is what limits your no-stop time, so cutting the nitrogen content lets you stay longer at a given depth before reaching your no-decompression limit. Many divers also report feeling less fatigued after nitrox dives, though the evidence there is mixed.
The catch: an oxygen depth limit
More oxygen sounds purely good, but at depth oxygen's partial pressure rises and too much becomes toxic. So each nitrox blend has a maximum operating depth that's shallower than air's — for example, a 32% blend is typically limited to around 33 m. That's why nitrox extends time, not depth, and why you analyse every tank and set your computer to the right mix.
Is it worth it for a new diver?
If you do several dives a day (on a liveaboard or a busy dive trip), nitrox can noticeably increase your total bottom time and is often worth it. For occasional single dives it matters less. Either way it's one of the most popular first specialties — and you'll understand it easily once you grasp how nitrogen drives no-decompression limits.
Frequently asked questions
Is nitrox better than air for diving?+
It's better for staying longer at recreational depths because it extends your no-decompression limits. It is not better for going deeper — the added oxygen gives nitrox a shallower maximum depth than air.
Does nitrox let you dive deeper?+
No — the opposite. The higher oxygen content means each nitrox blend has a shallower maximum operating depth than air. Nitrox is about more bottom time, not more depth.
Do I need a course to dive nitrox?+
Yes. Enriched Air (Nitrox) is a short specialty course — usually a day of theory — covering how to analyse your tank, set your computer and respect the oxygen depth limit. You can take it once you're Open Water certified.