Choose a base, not an island count
Compare Phuket for beaches and Old Town, Samui for varied beach and activity days, or Tao when diving and snorkelling drive the trip.
Krabi cliffs or Gulf island days? Put the coast and the season together before you book the beach part of Thailand.

Start with your travel month, choose the coast, then decide how much moving around the beach leg really needs. Phuket, Ko Samui and Ko Tao are different base decisions—not a checklist.
Phuket gives you several beach areas and Old Town; Ao Nang is a mainland Krabi base for boat outings. Railay makes the boat leg part of your arrival, while Ko Lanta suits a slower stay around one beach. Compare those trade-offs before choosing the hotel.
Seasonal patterns vary between years. Sea conditions and actual transport operations need a separate check.
Use three nights in Bangkok, four in Chiang Mai and five at one coastal base, then return for a final Bangkok night. The day-by-day route includes travel days and separate Ao Nang and Samui versions.
Plan a 14-day Thailand itineraryCompare Phuket for beaches and Old Town, Samui for varied beach and activity days, or Tao when diving and snorkelling drive the trip.
Ao Nang can be your mainland base with an optional boat outing. Staying at Railay makes passenger-boat access part of the hotel arrival too.
A mainland day and a boat excursion do not have the same dependence on sea conditions.