Phuket, Samui, Phangan, Tao, Krabi and Lipe belong to different transport systems and seasonal patterns. Repeated island changes turn a short holiday into check-outs, piers and waiting. For seven nights, one principal island and one secondary island is usually enough.
The Andaman side includes Phuket, Krabi, Lanta and Lipe, with generally more stable seas from late year into spring. The Gulf includes Samui, Phangan and Tao and follows a different rain pattern. Ferries and sea conditions must be checked for the actual date; a national weather forecast does not describe every island.
Phuket has the broadest flight and hotel choice for families and first visits. Samui supports a complete high-end resort stay. Tao leans diving. Phangan contains both parties and quiet bays. Lanta and smaller islands move more slowly but have fewer transport and medical resources. Begin with the people travelling and the desired daily life, not a ranking.
Beyond boat time are hotel check-out, road transfer, pier waiting and weather delay. Avoid a tight connection from an international arrival to the last boat, and return to an island with reliable airport access before departure. Large luggage, young children and motion-sensitive travellers benefit most from fewer moves.
We place monsoon, flights, piers, minimum hotel stays and activities into one map and state which connections carry risk. AI lists islands; a human advisor decides which one to remove so the remaining time feels like a holiday.