Using an eSIM in Koh Samui

What Koh Samui is like on a phone

Samui takes two kinds of visitor who live quite differently: one books a resort and barely leaves its beach, the other rents a bike, circles the island daily and hops to the neighbouring islands. The island's shape explains almost everything about its signal — houses, shops and hotels cling to the outer ring beside the sea, while the middle is forested mountain with hardly anybody in it. So long as you stay on the ring road, things run smoothly.

When you land

Samui airport (USM) is an open-sided field where you walk from the aircraft to a garden terminal. Turn the eSIM on before the wheels touch, because the walk from plane to transfer is short and you will want to message the hotel straight away. The other common route, and the cheaper one, is to reach the mainland by air or road and take the ferry from the Surat Thani side to a pier on the island's west coast; the line thins noticeably in mid-channel. Confirm your pick-up before the boat leaves, and allow slack, because sailings shift with the sea state.

Where coverage changes

The ring road and the beaches with shops along them carry service almost continuously. The change comes when you turn inland onto the roads climbing to a waterfall or a viewpoint: narrow, steep, roofed over by canopy, they cut out in stretches and in places go for a long while. The coves tucked behind the southern headlands are clearly weaker than the big east-coast beaches. On a day out to a neighbouring island, the line goes once you are past the shore into open water and does not return until the destination island is in sight.

What a day here costs in data

An ordinary day here runs about 700MB to 1.3GB, mostly maps while riding the ring road, finding somewhere to eat, and the evening upload. Stay a while and work from the cafes on the east side and the figure follows your camera hours. Boat days use less than you expect, because you are outside coverage for hours and then upload the lot at once back at the room — which is when the number jumps.

Districts travellers ask about

• Chaweng — The long east-coast beach with the island's densest run of shops and rooms; strong the length of the back road, though in the evening rush a ride takes longer to arrive simply because everyone is ordering at once.
• Lamai — The southern beach, quieter than Chaweng but still continuously built up; fine along the beach road, while a place up on the slope behind depends on whether it faces the sea or the hill.
• Bophut — The old fishing village in the north with a single lane along the water; consistent, and a sensible base if you have calls, because it is near the main road without the churn of the big beaches.
• The island's interior — Forested mountain with waterfalls and viewpoints, reached by narrow steep roads; long gaps with nothing at all in places, so do not plan on calling a ride back from up there.

Day trips out of the city

• The Ang Thong marine park — Boats leave early for a cluster of uninhabited limestone islands, and you will be outside coverage for most of the day. Warn whoever is waiting beforehand, and save the photos for the ride home.
• Over to Koh Phangan and Koh Tao — Fast boats cross open water; the line goes in the middle and returns near the far pier. If you are heading for one of the beach gatherings that draw thousands, expect rides and messages to be slow that night.
• The waterfalls and the inland roads — Up into the middle on narrow roads roofed by trees, with the line gone for most of the climb; download the map before you set off, and avoid going in rain, when the surface is slick and it darkens early.