Ko Tao

Ko Tao is around twenty-one square kilometres of granite and forest north of Ko Pha Ngan, and it certifies more entry-level divers than almost anywhere else on earth. The economics are simple: sheltered bays, warm water, short boat rides to the sites and a dense cluster of schools competing on price. Sairee Beach on the west coast holds most of the accommodation and the sunset crowd, while Chalok Baan Kao in the south and a run of small east-coast bays stay quieter. Snorkellers get plenty without a tank, with blacktip reef sharks in the shallows at Shark Bay and coral close in at Mango Bay. Ko Nang Yuan, three islets joined by sandbars, sits just offshore.

What you actually see

• Shark Bay - blacktip reef sharks in waist-deep water on the right tide.
• Ko Nang Yuan - three islets tied together by sandbars, with a separate landing fee.
• Chumphon Pinnacle - deep granite towers for experienced divers, weather permitting.
• The east-coast bays - Tanote and Hin Wong, rocky and slow compared to Sairee.

When to go

Diving works all year, but the water is clearest from March to May and again in September. The crossing from Chumphon or Surat Thani gets rough from late October into December, when the northeast monsoon brings most of the island's rain and boats are sometimes cancelled outright. Book courses on arrival rather than online; prices are similar and you can look at the boats first.

Honest expectations

Popular sites carry a lot of divers at once, and visibility swings from excellent to soupy with no warning. The roads are steep and badly surfaced, scooter accidents are common, and rental disputes over scratches are a recurring complaint. Several viewpoints sit on private land and charge separately. Nang Yuan restricts what you can bring ashore and is crowded by late morning.

Nearby

Ko Pha Ngan an hour south, and Chumphon on the mainland.