The best time of year to snorkel Koh Lanta

Koh Lanta has two seasons and they make a real difference to snorkeling. This is not a marketing point — trips genuinely stop running in parts of the year.

High season: November to April

The Andaman is calm, the sky is mostly clear, and visibility is at its best. Every trip on this site runs, the national park is open, and the sea is flat enough that seasickness stops being a concern.

January and February are the most reliable months. December and the New Year period are the busiest and the most expensive.

Shoulder: May and October

Changeable. Some beautiful days, some washed out ones, and boats cancel at short notice when the swell comes up. Prices drop and the islands are quiet.

If you travel in these months, build a spare day into your plans so a cancellation does not cost you the trip entirely.

Low season: June to September

South-west monsoon. Strong onshore wind, big swell on the west coast, and reduced visibility from run-off and churned sand.

Mu Ko Lanta National Park normally closes for part of this period, which takes Koh Rok off the table entirely. Sheltered trips — the mangroves, the east coast, sometimes Koh Haa — often still run.

A practical note

We cancel trips when the sea is not safe, and we refund in full when we do. That is not a policy anyone enjoys using, but it is a lot better than the alternative.