Nha Trang

The routine barely varies. Boats leave the town harbour in the morning, make a short run out to the island cluster, dive, anchor up for lunch and the surface interval, dive again and are alongside by mid-afternoon. The marine park fee is charged separately, usually collected on the day. Boats are shared and groups run large, with courses and fun divers on the same deck, so it is worth asking how many divers one guide will be taking before you book anything.

The rock underwater is the same granite that shapes the coastline: rounded blocks stacked into slopes, with gaps, short tunnels and shaded overhangs between them instead of continuous reef. That structure is what carries the diving. Every crevice is a hiding place, and the silt and rubble collecting between the blocks is where the small animals settle. Profiles stay shallow and flat, so a dive here is an hour of slow, deliberate searching rather than a descent, a tour and an ascent.

Which sites you get can move around, since parts of the protected area have been closed to diving at times while managers give damaged coral room to recover. That matters less here than it would elsewhere, because the small life is spread across every boulder slope in the bay rather than concentrated on one reef. The trade-off is an honest one: no current, no size, nothing happening in the water column. What you get instead is an hour of close-range looking, which is what the macro photographers come for.