Covers Phuket, Koh Samui, Koh Lanta, Koh Phi Phi, Bali, Palawan, the Maldives, Mauritius, the Seychelles and Zanzibar, with visa and park rules checked at the source.
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April is the turning point between Thailand's two island coasts. The Thai Meteorological Department counts March to May as the hottest time of year, and on the Andaman side, home to Phuket, Phi Phi and Koh Lanta, rain starts to build ahead of the southwest monsoon in mid-May. Koh Samui, in the Gulf of Thailand, is in the middle of its best season.
So Samui takes first place at 7.79 out of 10, with 88°F (31°C) highs, an 89°F (32°C) sea and 4.2 inches (107 mm) of rain. Phuket is close behind at 7.62. The cards below give the order; the sections explain why the coasts swap places and what to expect from April heat.
Score = 55% this month's weather + 45% the island's other five factors. How we score
| # | Island | Score | High °F | Sea °F | Rain (in) |
|---|---|---|---|---|---|
| 1 | Koh Samui | 7.8 | 88 | 89 | 4.2 |
| 2 | Phuket | 7.6 | 89 | 87 | 5.0 |
| 3 | Koh Phi Phi | 7.0 | 89 | 87 | 5.0 |
| 4 | Koh Lanta | 6.1 | 92 | 88 | 7.8 |
1Samui is first in April because its Gulf coast is in its best season while the Andaman side heads toward the monsoon. Its April weather score is 9.0: 88°F highs, an 89°F sea and 4.2 inches of rain. Chaweng's long beach and the sheltered bay at Choeng Mon suit couples and families. A well-reviewed Chaweng 4-star cost $84 in January and $58 in July, and April should fall between. Plan sightseeing early; afternoons are hot.
2Phuket is a close second. Its April weather score drops to 8.3 as rain rises to 5.0 inches ahead of the southwest monsoon, with 89°F highs and an 87°F sea. It still has the most to do of the four, an 8.5, from Phang Nga Bay to Old Town. Patong 4-stars ran $76 in January and $32 in July. If you want variety over calm, pick Phuket over Samui; the gap is 0.17 points.
3Phi Phi carries Phuket's April weather, an 8.3 with 89°F highs, an 87°F sea and 5.0 inches of rain, so the gap to Phuket is all in the other factors. It scores 5 for things to do and 6.8 for value, with 4-star rooms from $86 to $187 across our two dates. April is still Maya Bay season, at $12 (400 baht) per foreign adult. Go for a night or two, not a week.
4Lanta falls to last in April. Its Krabi data shows 7.8 inches of rain and 92°F highs, which cuts its weather score to 6.1, the lowest of the four this month. It also gives up 0.4 points as an island its own page recommends only from November to April. The beaches are still long and quiet, the sea is 88°F, and rooms are cheap, 3-star from $8 in July. Choose it for price, and swim in the mornings.
In this guide
Each score is 55% the island's April weather score and 45% its year-round score for beaches, things to do, access, value and crowds. Islands our pages rate as worth it only for some travelers lose 0.4 points. The weather score starts to fall when highs pass 88°F, and rainfall carries the most weight. The method is on how we score islands.
Weather is read at each gateway airport: Phi Phi uses Phuket's data and Lanta uses Krabi's, on the mainland.
Thailand's islands sit on two seas. The Andaman coast gets the southwest monsoon from about mid-May to mid-October, with its rain peak in September. The Gulf coast gets its heavy rain from the northeast monsoon, mostly mid-October to early December. Each coast's dry season is the other's wet one.
In our dataset, Samui has the better weather score from February to October. In February the gap is too small to beat Phuket's lead on things to do and price. By April it is 9.0 against 8.3, large enough to put Samui first, and it stays first through October. Phuket returns to the top in December. For the mid-summer gap, see July.
April is hot everywhere. Highs run from 88°F on Samui to 92°F on Lanta, and the sea is near its warmest, 87°F to 89°F. That is pleasant for swimming and hard work for midday sightseeing. Plan temple visits, Phuket Old Town walks or Samui's Na Muang waterfall for early morning, and keep the afternoon for the water or the pool.
On the Andaman side, rain roughly doubles from March to April in our Phuket data, from 2.5 to 5.0 inches (63 to 127 mm), as the monsoon approaches. Sea conditions can change quickly; follow the flags on west-coast beaches.
We price every island on January 13 and July 14, 2027. April sits between high and low season, so expect prices between the two. The cheapest well-reviewed 4-star hotels on Kayak ran $58 to $84 in Chaweng, $32 to $76 in Patong, $52 to $84 on Lanta and $86 to $187 on Phi Phi, taxes and fees in.
No US airport flies nonstop to Thailand's islands. For Samui, fly to Bangkok and connect on Bangkok Airways, or connect in Singapore on Scoot; the cheaper route is a flight to Surat Thani and the ferry from Don Sak. US citizens get 30 days visa-free since September 15, 2026, down from 60, and must file the free Thailand Digital Arrival Card within 72 hours before arrival. See the passport rules guide and the world April ranking.
Transfers from the main beaches, lunch and entrance fees are included.
Rating as shown on GetYourGuide
Lunch and snorkel gear are included; the national park fee is only included if you pick that option. Expect a crowded, fast day; Maya Bay closes for August and September.
Rating as shown on GetYourGuide
Price is per boat, so it suits a group; the park fee (400 THB per adult) and lunch are not included.
Rating as shown on GetYourGuide
Booking through these links supports this site at no cost to you. Prices move by date, so we do not print them here; the official prices we checked are in the page above.
Yes, if you can take the heat. It is the hottest stretch of the year, with highs of 88°F to 92°F on the four islands in our data, but rain is still moderate. Koh Samui has the best April weather.
Samui, narrowly: 7.79 against 7.62. Samui's April has less rain, 4.2 inches against 5.0, and a slightly cooler afternoon. Phuket still has more to do and is a fine choice.
The southwest monsoon arrives around mid-May, according to the Thai Meteorological Department, and lasts until about mid-October, with the heaviest rain in September. April is the run-up: Phuket's April rain in our data is about twice March's.
It is the weakest of the four this month. Its Krabi weather data shows 7.8 inches of rain and 92°F highs. Its island page rates it worth it from November to April, so April is the last good month, not the best.
About 87°F to 89°F (31°C to 32°C) around all four islands in our data, close to the warmest of the year.
Further reading
