In short
A long flat island, one road, beaches following one another from north to south. Lanta draws the people who find Phuket too loud and Koh Phangan too party-minded.
Life concentrates on the west coast. The south, towards the national park, is markedly quieter and markedly less equipped.
What it really costs
Rents are among the lowest of the Thai islands, but long-term supply is limited: mostly bungalows let by the week.
Everything arrives by ferry, which pushes up groceries. Local restaurants stay very cheap.
When to go
The dry season runs November to March. From May, the monsoon closes part of the accommodation and the sea becomes too rough for boat trips.
The January high season fills the island and doubles the rates.
What nobody tells you
The connection is decent but not reliable everywhere: in the south of the island it drops regularly. A mobile plan with tethering is not a luxury.
Off season, half the businesses close and the island genuinely empties.