Pattaya & the Sattahip Wrecks

A diving day here starts at one of two piers, and which one sets the whole shape of it. Boats for the near and far islands leave Bali Hai Pier or one of the mainland beaches; a return speedboat charter out to the Ko Phai group is roughly 23 km and two hours. The wreck and technical trips run instead from the pier at Chong Samae San Village, some twenty kilometres south in Sattahip, booked either through a Pattaya shop or in the village itself. One Pattaya operator runs 12 m speedboats, holding a 20 m charter vessel back for rough seas.

The two halves dive nothing alike. The islands are hard-coral reef over rock, beginning at 3 m and sloping into sand between 8 and 30 m, with big sponges and sea fans on the exposed tips and macro ground below - nudibranchs, seahorses, tiger gobies. The wrecks are steel sitting in open channel water: the Hardeep on her starboard side at 27 m, the Bremen's 88.5 m hull between 19 and 24 m. Barracuda, batfish, sweetlips, marbled and giant black stingrays and the occasional hawksbill turtle work the metal.

The outer islands are Royal Thai Navy water. Overnight stays are not permitted, the southernmost rocks are still used as a live-fire practice target, with bullets and missiles on the bottom, and Koh Nen sits beside a military unit as a training and conservation site. Current deserves respect: the Bremen lies in a channel that runs hard, the Samaesan reefs drift on a rising or falling tide, and North Rock can be slack on one side and running hard on the other. Surface traffic is a genuine hazard, and a surfacing diver was killed by a speedboat propeller off Ko Laan in 2006.

It suits divers based in Bangkok, ninety minutes away by road, who want steel rather than coral, and it suits technical divers above all: the Samaesan cluster is a training ground with TDI, PSAI and IDEST shops, a PADI distinctive specialty for the Hardeep, and the deepest sites in the Gulf within a day boat's range. Worth being clear that this is one destination on paper and two clusters in practice, worked from separate piers on separate days. Divers who want dependable visibility and reef instead of wrecks should look at Koh Tao or the Andaman coast.