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 Yao Noi: Season in Phang Nga Bay

Sheltered water changes the season

Koh Yao Noi is on the Andaman side of Thailand, so its calendar matches Phuket's: dry from November to April, monsoon from May to October. What makes it different is where it sits — inside Phang Nga Bay, with Phuket to the west taking the brunt of the weather.

Kayaking among the limestone in Phang Nga Bay

That shelter matters. When the west coast of Phuket is closed off by swell and red flags, the bay behind it is usually still workable: the kayaking and the boat trips out to the Hong Islands run on far more days than the open-sea trips do. The rain is the same; the sea is not.

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In short

Koh Yao Noi seasons

November–April: dry season, calm bay, everything open
May–October: monsoon, green, very few visitors
The bay is sheltered — calmer than Phuket's west coast
Best value: November and late April
Busiest: Christmas to mid-January, and still quiet by island standards

The dry season, month by month

November is the island at its greenest and freshest, just after the rains and before prices rise. December to February is the peak: dry, clear, reliably calm, and the busiest the island ever gets — which here still means quiet.

March and April are hot and dry, with April the hottest month of the year and Songkran, the national water festival, in the middle of it. Late April is the last of the settled weather and one of the better-value windows of the year.

Good to know

Planning around the weather

Boat trips into the bay run on more days than open-sea trips from Phuket.
Check the tide as well as the forecast — it shapes the day more than the weather does.
The rice fields are at their best from about July to October.
Songkran in mid-April is a country-wide water fight; expect to get soaked.

Green season on a farming island

From May to October the rain comes, and Koh Yao Noi takes on a different character. The rice paddies fill, the island turns properly green, the water buffalo have somewhere to stand, and the few visitors thin out to almost nobody.

Less closes here than on the more tourist-dependent islands, because the island has an economy of its own — but check your hotel's dates, and expect boat trips to be weather-dependent. If you can accept rain in bursts, this is one of the better islands to see out of season.

Month by month

January	Dry, clear and calm — the peak of the season
February	Hot, dry and reliable, best visibility in the bay
March	Hot and dry, quieter than the peak
April	Hottest month, Songkran mid-month, season ending
May	First rains, prices fall, the island empties
June	Warm rain in bursts, green and very quiet
July	Wet, the rice paddies fill, plenty of sun between showers
August	One of the wettest months, boat trips weather-dependent
September	Wettest and quietest month of the year
October	Rain easing, the island at its greenest
November	Fresh, green and calm — the best value month
December	Dry and clear, prices climb towards Christmas

Frequently asked questions

When is the best time to visit Koh Yao Noi?

November to April for dry, calm weather. November and late April give the same conditions as the peak without the Christmas prices.

Is Koh Yao Noi worth visiting in the rainy season?

More than most Andaman islands. It sits sheltered inside Phang Nga Bay, so the sea stays usable on days when Phuket's west coast does not.

Does Koh Yao Noi close in low season?

Less than the tourist-dependent islands, because it has its own fishing and farming economy. Still, confirm your hotel's dates before booking.

What is the weather like compared to Phuket?

The rain follows the same calendar, but the sea is calmer. Being inside the bay means swell and red flags are far less of a problem.

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Best time to visit Koh Yao Noi