When is the best time for diving on Koh Tao?

Roughly March to September, when seas are calm and visibility at its best. Diving runs year-round, but October to December brings wind, rain and reduced visibility.

When is the rainy season on Koh Tao?

October to December, peaking in November. Like the rest of the Gulf, Koh Tao stays largely dry through the European summer months.

Can ferries to Koh Tao be cancelled?

Yes — in the November–December monsoon, rough seas occasionally halt crossings from Chumphon and Surat Thani for a day or two. Build slack into travel plans in those months.

When can you see whale sharks at Koh Tao?

Sightings happen year-round and are never guaranteed. Many divers report clusters of sightings in the settled months around March–May and again around September–October.

Best Time to Visit Koh Mak: Season and What Closes

The eastern Gulf calendar, not Samui's

Koh Mak is in the Gulf of Thailand, but like Koh Chang and Koh Kood next door it runs on the south-west monsoon: dry from November to April, wet from May to October, with the heaviest rain from July to September.

That is the same calendar as Phuket and the opposite of Koh Samui's. It is the single most useful thing to know when comparing the eastern islands with the Samui archipelago for a trip in October or November.

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In short

Koh Mak seasons

November–April: dry season, calm clear sea, everything open
May–October: rains, many places closed, fewer boats
Best value: November and late April
Busiest and dearest: Christmas to mid-January
Closest island to the Koh Rang snorkelling trips

What the dry season looks like

From November to April the sea is flat and clear, the boats run reliably, and the snorkelling trips out to the Koh Rang marine park go most mornings — Koh Mak is the closest island to them, which is one of its quiet advantages.

December to February is the peak, with the most dependable weather and the highest prices, and Christmas and New Year booked out well ahead. March and April are hot and dry, with April the hottest month of the year and Songkran in the middle of it. Late April is often the best value week of the season.

Good to know

Planning around the weather

In low season, confirm the hotel, its restaurant and the boat before booking flights.
Snorkelling trips to Koh Rang are most reliable from December to March.
Do not assume Koh Mak shares a season with Koh Samui — it does not.
Songkran in mid-April is a country-wide water fight; expect to get soaked.

Low season on a small island

Koh Mak has never had many places to stay, so when a large share of them close from May to October the island empties out completely. Boat services are cut back, some crossings are cancelled in rough weather, and the restaurants that stay open are few.

The rain comes in bursts rather than all day and the island turns intensely green, so it is not a washout — but it is a season for people who want almost nobody around and are willing to confirm that their hotel, its kitchen and a boat are all running before they book.

Month by month

January	Dry, calm and clear — peak season
February	Hot and reliable, the best water clarity
March	Hot and dry, quieter than the peak
April	Hottest month, Songkran mid-month, season ending
May	Rains begin, places start closing, prices fall
June	Wet and very green, few visitors
July	Heavy rain, boat crossings less reliable
August	One of the wettest months, most of the island shut
September	Wettest and emptiest month of the year
October	Rain easing, the island starts reopening
November	Everything open, green and calm — best value
December	Dry and clear, prices climb towards Christmas

Frequently asked questions

When is the best time to visit Koh Mak?

November to April. November and late April give the same calm sea as the peak at noticeably lower prices.

Does Koh Mak close in low season?

A large share of it does, from about May to October. On an island this small, that means very little is left open.

Does Koh Mak have the same season as Koh Samui?

No. Koh Mak is dry from November to April, the same as Phuket and its neighbours Koh Chang and Koh Kood.

Is Koh Mak good for snorkelling?

It is the closest island to the Koh Rang marine park, and the day trips out there are the main excursion. They run most mornings from December to March.

Travel guides

More Koh Mak and eastern Gulf guides, plus the rest of Thailand's islands.

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Koh Mak

Koh Mak

Best time to visit Koh Mak