Nitrox

France Plongée runs a nitrox blending station at the Koh Phangan centre — two Coltri MCH16 compressors that fill tanks with air or nitrox blends up to 40%. The specialty course that lets you use those fills takes less than a day to complete, which makes it a practical add-on to any multi-day stay.

Nitrox replaces a portion of the nitrogen in a standard air mix with additional oxygen. The effect in practice is a longer no-decompression limit at a given depth and reduced nitrogen loading over repeated dives — useful when you're doing two dives a day across several days, which is the normal rhythm here.

The prerequisite is an open-water certification in a natural water environment, with a minimum age of 15. The theory component covers gas physics, oxygen toxicity limits, planning tools, and how to analyse a blend before diving it. The practical side is done in the water at Haad Salad or on a scheduled boat trip.

For divers staying multiple days in the Phangan area and planning to dive Sail Rock repeatedly or push depth at Chumphon, picking up the nitrox card early in the trip is worth considering.