Koh Samae San

Koh Samae San is a small Royal Thai Navy-managed island off Sattahip, run partly as a marine conservation project that’s kept its reef in noticeably better shape than more developed islands nearby. Foreign visitors pay 600 THB regardless of age; Thai adults pay 300 THB and children under 12 pay 220 THB. That fee covers the round-trip boat crossing and basic travel insurance, not activities. Snorkelling is sold on the island as a package that includes a life jacket, snorkel gear, a short briefing and the boat out to the snorkel site; kayaks (charged by the hour) and glass-bottom boat trips (charged per trip) are separate.

Watch out: The island caps daily visitors at 300 people, and slots go through an official booking system (samaesarnisland.com) that opens three days ahead at 08:30. This isn’t a walk-up destination. Arrive without a booking and there’s a real chance of being turned away at the pier.

The payoff for the navy’s restrictions is a reef that still has real coral cover close to shore. Parrotfish and small schools of angelfish move through brain coral formations a short swim from the sand, and the island’s compact size means a single visit can cover two or three distinct snorkelling spots rather than one long swim. Above water, rocky headlands give views back across the Gulf of Thailand, and a few small sandy patches work for a picnic between snorkelling sessions. Glass-bottom boat rides are available for anyone who’d rather see the reef without getting in the water.

Speedboats cross from the pier at Sattahip in 15-20 minutes. Most visitors come from Pattaya or Jomtien first, since that’s the nearest tourist base. Figure 45 minutes to an hour by road to Sattahip depending on traffic, longer from Bangkok. There’s no overnight accommodation and the navy doesn’t allow camping, so this is strictly a day trip; plan to be back at the pier by mid-to-late afternoon since the last returning boats run before the 17:00 close.

Insider Tip: Book the earliest available crossing. Morning seas are calmer, visibility is better before the afternoon breeze picks up, and you’ll have more of the capped 300-visitor quota’s worth of beach space to yourself before later boats arrive.

The Pattaya hub covers transport from the main tourist base, and nearby Chong Samaesan Village and the Thai Island and Sea Natural History Museum on Samaesan mainland make good add-ons if you have a full day in the area.