Enriched Air Nitrox

Nitrox is a breathing gas mixture with a higher percentage of oxygen than regular air. Standard air is roughly 21% oxygen — nitrox mixtures used in recreational diving typically run between 32% and 36%. That higher oxygen content means less nitrogen in the mix, which is the gas that accumulates in your body during a dive and limits how long you can safely stay down.

The practical result is longer bottom times and shorter surface intervals. On a single dive the difference is noticeable — a nitrox diver can extend bottom time at a given depth compared to someone breathing air. Across a day of multiple dives, the cumulative effect is significant. Most divers also report feeling less fatigued at the end of a nitrox diving day, which is consistent with the reduced nitrogen load.

Around Koh Tao nitrox is widely used and widely available. If you’re doing fun dives, a Sail Rock day trip, or working toward Divemaster, you’ll encounter nitrox-equipped divers regularly. The specialty is worth having simply because the option to use it will come up, and it’s a one-day course with an immediate practical payoff.

The course covers the theory behind enriched air diving — oxygen toxicity limits, planning dives with nitrox, analysing your cylinder, and setting your dive computer correctly for a nitrox mix. There’s no complicated science involved, just a solid understanding of how to use the gas safely and get the most out of it.