Thailand, Vietnam and Cambodia eSIM

The short version

This is the trip where it’s closest. Thailand and Vietnam both have cheap local plans, so three separate eSIMs can cost about the same as one for the whole trip. The table above shows today’s prices. Where they’re within a euro or two, take the single eSIM: one QR code, no switching lines at the border, and nothing to install halfway through the trip.

Use your phone a lot? Then the single eSIM usually pulls ahead, because one big bundle costs less per GB than three smaller ones.

How you’ll travel it in 2026

As of October 2026, the land border between Thailand and Cambodia is closed to travellers, the Aranyaprathet–Poipet crossing included. It has been shut since the border conflict of 2025. So the classic bus from Bangkok to Siem Reap is off. Most people now fly from Bangkok to Siem Reap or Phnom Penh, and then cross from Cambodia into Vietnam over land, or the other way round.

For your eSIM that changes nothing, and that’s the point of a single one: it doesn’t care whether you arrive by plane or bus. It switches to the local network wherever you land.

The networks

Thailand: AIS and True Move, both with 5G.

Vietnam: Mobifone, Viettel and VinaPhone, all three with 5G where it’s built. Viettel and VinaPhone switched on 5G in late 2024, starting with the provincial capitals, tourist sites and airports; outside those you’ll mostly be on 4G, which is plenty.

Cambodia: Cellcard and Metfone, 4G only. In Opensignal’s February 2026 report, Cellcard won the most awards.

These are the networks on the Asia eSIM, which is the one our planner picks for this route. The local Thailand, Vietnam and Cambodia eSIMs use the same networks.

How much data

Three weeks with normal use (maps, ride apps, messages and some socials) comes to about 13 GB. A month comes to about 18 GB. The table above prices both light and normal use for 14, 30 and 60 days.

The Asia plan stops when the data is used up; it doesn’t slow down. If you’re in doubt, take the next size up. Buying a second eSIM halfway through always costs more than the step up.

Tips for the trip

• Install at home, on wifi. The plan only starts when you first connect at your destination.
• Grab works in all three countries, so you’ll use it more than you think. In Vietnam the local favourite is Be, and Xanh SM for electric taxis.
• Flying between Bangkok and Cambodia? Your eSIM switches network when you land. Give it a minute, or switch flight mode off and on.

Sources: on the border, Bangkok Post and Khmer Times; on 5G in Vietnam, VnEconomy; Opensignal, Cambodia, February 2026. Networks per country come from our own catalogue.