Banana Pancake Trail eSIM

The short version

For a trip of up to a month, one regional eSIM beats four local ones. You install one QR code at home, and at every border your phone moves to the next network by itself. No hunting for a SIM shop in Huay Xai, no swapping plastic on a bus.

Stay two months or longer, and the maths turns. Four local eSIMs, each bought for the stretch you’re actually in that country, come out a little cheaper than two periods of a regional one. The table above shows both, at today’s prices.

Heads-up: Thailand to Cambodia over land

As of October 2026, the land border between Thailand and Cambodia is closed to travellers, including the busy Aranyaprathet–Poipet crossing. It has been shut since the border conflict of 2025, and no reopening date has been announced. Do the loop the other way round: Thailand, Laos, Vietnam, then Cambodia over land from Vietnam, and fly out of Cambodia. Check the latest with Thai immigration before you plan around it.

Laos is the reason for the regional eSIM

There’s no Laos-only plan in our shop. Laos runs on the Asia eSIM, which also covers Thailand, Vietnam and Cambodia. That’s what makes the regional option the obvious one for this route: you’d need a regional plan for Laos anyway.

In Laos the Asia eSIM uses ETL and Lao Telecom. Unitel, the network with the widest coverage outside the cities, isn’t on it, so be realistic. In Luang Prabang, Vang Vieng and Vientiane you’ll be fine. On the two-day slow boat down the Mekong and in the hills of the north, expect long stretches without signal on any network. Download offline maps and your bus or boat tickets before you leave town.

Country by country

Thailand. The eSIM uses AIS and True Move, both with 5G. In Opensignal’s June 2025 report, AIS scored highest for consistent quality. AIS says its 5G reaches more than 95% of the population; that’s AIS’s own figure. If the signal is weak on an island, pick the other network by hand in your phone’s network settings. It often helps.

Laos. ETL and Lao Telecom, see above. Good in town, thin in between.

Vietnam. Mobifone, Viettel and VinaPhone, all three with 5G. Viettel won the most awards in Opensignal’s August 2026 Vietnam report, with Mobifone close behind. Three networks on one eSIM gives you a fallback: if one is weak in the mountains of the far north, pick another by hand.

Cambodia. Cellcard and Metfone, 4G only. In Opensignal’s February 2026 report, Cellcard won the most awards. 4G is plenty for Siem Reap, Angkor and Phnom Penh.

How much data

A month on this route, using your phone like most travellers (maps, ride apps, messages, a few stories), comes to about 18 GB. That’s why the table picks 20 GB for 30 days of normal use. Light users who stick to maps and messages get by on 10 GB.

One thing to check before you buy: the Asia plan stops when its data is used up. It doesn’t slow down, it stops. If you’re unsure, take the next size up. It costs less than buying a second eSIM halfway through.

Before you go

• Install the eSIM at home, on wifi, a day or two before you fly. It only starts counting when you connect in the first country.
• Keep your own SIM in for bank texts, but turn data roaming off on it.
• At every border, give your phone a minute to find the next network. Still nothing? Switch flight mode on and off.
• Crossing by land into Laos, Vietnam or Cambodia? You’ll want the visa rules and the bus times offline. Screenshot them before you leave the last town with wifi.

Sources: Opensignal, Thailand, June 2025; Opensignal, Vietnam, August 2026; Opensignal, Cambodia, February 2026; AIS quarterly results on 5G population coverage; on the border, Bangkok Post and Khmer Times; for Laos, operator comparisons on internetlaos.com. Networks per country come from our own catalogue.