Thailand itineraries: 1 week, 2 weeks and 3 weeks

Match the trip to the nights you actually have, not the nights you wish you had. Each row below is the parent country plan, with the transport that makes it work.

Start with Bangkok. Three or four nights covers the Grand Palace, Wat Pho, a river boat and enough street food to stop chasing it later. Ayutthaya works as a day trip by train or minivan, but one night there beats the rushed version.

Then pick one direction, not two. North to Chiang Mai for old-city temples, cooking classes and mountains; south to Krabi, Phuket or the Gulf islands for beaches. Flying Bangkok–Chiang Mai or Bangkok–Krabi takes about an hour and a half and costs far less time than the overnight bus or train, which eats a night and leaves you tired.

If you have 14 days, the classic loop adds Chiang Rai in the far north, then a flight south (often connecting through Bangkok) to Khao Sok for two nights of rainforest and lake raft houses, finishing on the Andaman coast at Krabi, Railay or Koh Lanta. Ayutthaya to Chiang Mai is a comfortable day train; Chiang Rai to the south is a flight day.

With 21 days, add Isaan from Khon Kaen or Udon Thani, or a second coast in the opposite season. Keep flying the long legs: overland Chiang Mai to the islands is a full day or more each way.

Thailand has two monsoon patterns, so the coast you choose depends on when you travel. The Andaman side (Phuket, Krabi, Koh Lanta, Koh Lipe) is driest Nov–Apr. The Gulf side (Koh Samui, Koh Phangan, Koh Tao) is driest Feb–Sep. Booking the wrong coast in the wrong month is the most common itinerary mistake.

The trips that fail try to cover Bangkok, the north and the islands in ten days. Each move costs half a day once you count the transfer to the airport, the flight and the ride to the hotel.

Overnight buses and trains look like a saving but rarely are: you arrive before dawn, cannot check in, and lose the next morning. Use them only on routes where the flight is expensive or the timing genuinely suits you.

Book domestic flights and popular island ferries ahead in Dec–Feb and around Thai holidays, when seats and rooms fill. Carry a little cash for boats, songthaews and small guesthouses; not every pier or stall takes a card.