Tao + Nangyuan Speedboat

This is the budget-friendly option for Koh Tao. You don't pick the route — the speedboat runs a fixed itinerary daily — but the itinerary is the popular one, and the company we book through has been doing it long enough that the timing is reliable.

What you trade for the price: about 25 other guests on the boat, a fixed lunch buffet rather than menu choice, and a fixed return time of 5pm regardless of how good the snorkel is. What you keep: the same three islands, decent snorkel gear, and a guide who actually speaks English.

Nangyuan is the headline. It's three islets connected by a tidal sand spit; you can walk from one to the other at low tide. The viewpoint above the middle island is the photo every Samui-Phangan-Tao traveller wants. We add: don't skip the western reef — it's a 5-minute walk from the boat-landing area, much shallower than the main bay, and full of parrotfish.

Koh Tao itself is bigger than people expect. Lunch is at one of the family restaurants near Mae Haad pier; the buffet is unremarkable but adequate. After lunch the boat moves to a second snorkel cove — usually Hin Wong or Kluay Thoen, depending on conditions.

The return crosses open water and tends to be bumpier than the morning. Sit aft for less spray, or skip the open seats and ask for one of the covered ones if you're prone to seasickness — book at least 24 hours ahead so the operator can hold them.