Things to Do in Koh Samui

Five things: an Ang Thong Marine Park boat day (฿1,200–2,500 plus the ฿300 park fee), the Big Buddha and Wat Plai Laem at 08:00, Fisherman's Village on a Friday evening for the Walking Street, the Coco Tam's fire show at 19:15, and a longtail to Pig Island from Thong Krut. Everything else on the island is a bonus around those.

Its beaches (Chaweng and Lamai above all), the 12-metre Big Buddha at Wat Phra Yai, Ang Thong Marine Park, its luxury resort and wellness scene, and its position as the gateway to Koh Phangan's Full Moon Party and Koh Tao's diving. It's Thailand's second-largest island and the Gulf coast's hub.

November. It's the wettest month, seas get rough enough to disrupt ferries, and Ang Thong Marine Park closes from 1 November to 15 December. Early December often stays wet before clearing by Christmas. The reliable window is January–August: February–April for the calmest seas, June–August for sunshine at lower prices while Phuket is in monsoon.

Koh Samui is smaller, calmer and easier: one ring road, beaches that suit couples and families, and dry-season weather from January to August. Phuket is bigger and louder, with more dining, more nightlife, and the Andaman boat trips (Phi Phi, Phang Nga Bay) on its doorstep, best November–April. Pick by season as much as by taste, because they take opposite monsoons.

Yes, with the right expectations: it's a comfortable resort island, not a castaway one. You get genuinely good beaches, easy logistics, world-class boat trips and strong food for mid-range money. If you want raw and undeveloped, its neighbours Koh Phangan and Koh Tao, both a short ferry away, carry more of that, which is exactly why Samui works as a base.

Four to five: one for the Ang Thong boat day, one for the temples, waterfalls and southeast corner, two for beaches with the fire show and Walking Street in the evenings, and a flexible day for Pig Island or a spa. Add nights on Koh Phangan or Koh Tao rather than stretching Samui past six.

Mid-priced by Thai standards. Budget rooms run ฿800–1,200, mid-range beach hotels ฿2,000–5,000, local meals ฿80–200, a one-hour massage ฿300–500. The two costs that stand out are getting there (Bangkok Airways' near-monopoly keeps Samui flights at ฿1,500–5,000 when the ferry-plus-train route costs a fraction) and the boat trips.

Ferries run all day from Samui's north and west coasts: Lomprayah catamarans take about 30 minutes for ฿250, Seatran about 45 minutes for ฿200. On Full Moon Party nights, special late boats run from Bangrak and Maenam so you can party and return the same night. Koh Tao is a further 75 minutes on the Lomprayah line, and I'd buy the combined ticket.

Base at Choeng Mon or Maenam for calm, shallow water, then: Pig Island by longtail (a 30-minute crossing to a beach with actual pigs), the Big Buddha causeway, Na Muang 1 waterfall (flat walk, swimmable pool), and Friday's Walking Street at 17:00 before it gets packed. Chaweng adds go-karts and a waterpark for wet days.

You can, but it's tight, around two hours each way by ferry, which leaves only midday hours on the island. It works if all you want is a snorkel tour from Mae Haad. For diving, take the overnight packages instead. Koh Phangan and Ang Thong are the day trips that actually fit inside a day.