All guides
Guida

Nitrox: what enriched air is and why it’s worth it

Nitrox is one of the most popular specialties, and for good reason: with just a few hours of training you extend the time you can spend at depth and finish your dive less tired. Let’s look at what enriched air really is, when it’s worth it and how to get the certification.

Top One Diving Club

Updated: September 2026

What Nitrox (enriched air) is

The air we breathe is made up of about 21% oxygen and almost all the rest nitrogen. Nitrox — also called EANx, “enriched air” — is simply air with a higher percentage of oxygen (usually between 32% and 40%) and therefore less nitrogen. Less nitrogen means less nitrogen your body absorbs during the dive.

It isn’t an “exotic” gas or anything risky: it’s a standard mix, used every day in recreational diving all over the world, with precise rules you learn in the course.

Why it’s worth it: the real benefits

The main benefit is more bottom time: since you absorb less nitrogen, the no-decompression limits get longer, so at the same depth you can stay longer (or do a second dive with more comfortable intervals).

Watch out, though, for a very common misconception: Nitrox extends the limit set by nitrogen, but it does not make the mix you’re breathing from that tank last longer. Consumption depends on depth, effort and breathing, exactly as with normal air. If you empty the tank before reaching the maximum bottom time, you simply don’t use the extra time Nitrox gives you: the benefit vanishes. In practice Nitrox is really worth it when it’s nitrogen (and not the mix in your tank) that limits you — that is, at medium depths and on repetitive dives, where with normal air you’d hit the no-decompression limit while you still have gas to carry on.

The second benefit, which many people appreciate even more, is feeling less tired after the dive: with less nitrogen in the system, many report finishing the day fresher, especially when doing several dives in a row, like on a trip.

When it really helps (and when it doesn’t)

Nitrox is at its best on repetitive dives and at medium depths (roughly 18-30 metres): that’s where the extra bottom time really shows. On a trip with two or three dives a day it makes a huge difference.

Note one point: Nitrox is not for going deeper. In fact, the more oxygen in the mix, the shallower the maximum allowed depth. Nitrox extends time, not depth: for that you need other paths (and the Deep Diving course).

How to get the Nitrox certification

The Nitrox specialty (Enriched Air Nitrox) is one of the quickest courses: it’s based mainly on theory — how to calculate the maximum depth based on the mix, how to analyse the tank before the dive, how to set the computer — and doesn’t necessarily require dedicated dives.

It’s already suitable for anyone with their first Open Water Diver certification, and it’s one of the first specialties we recommend, because it immediately improves the quality of every future dive.

Nitrox at Top One Diving

With us you learn to use enriched air safely, with the tank-analysis procedure and proper planning right from the start. It’s a small step that improves all your following dives, at sea as on a trip. Talk to us: we’ll tell you whether, for the way you dive, Nitrox is right for you.

FAQ

Does Nitrox let me go deeper?

No, it’s the opposite: the more oxygen in the mix, the lower the maximum allowed depth. Nitrox serves to extend bottom time and reduce absorbed nitrogen, not to go deeper.

Does the mix in my tank last longer with Nitrox?

No, this is the most common misconception. Consumption depends on depth, effort and breathing, not on the type of mix: with Nitrox you use gas just like with normal air. Nitrox only extends the limit set by nitrogen, so if you finish the tank before that limit you don’t use the extra time. It’s worth it precisely when it’s nitrogen that stops you before the mix in the tank, that is at medium depths and on repetitive dives.

Do I need experience to take the Nitrox course?

No: you just need your first certification (Open Water Diver). In fact it’s one of the first specialties we recommend, because it immediately improves every dive.

Does the Nitrox course include dives?

The core is theory and “dry” practice (tank analysis, calculations, computer setup). Dives aren’t always mandatory: we’ll explain based on your path.

Do I need special equipment for Nitrox?

For mixes up to 40% standard recreational equipment is fine. What changes is the procedure: analysing the tank and setting the computer correctly before you dive.

How long does the Nitrox course take?

It’s among the quickest courses: it’s often completed in one session, between theory and the practical part of analysis and planning. Contact us for dates.