Vietnam, Thailand and beyond: the best eSIM for a South-East Asia trip

South-East Asia trips rarely stay in one country. Bangkok to Chiang Mai, then Hanoi, then a week in Bali is a normal three-week route for Australians, and each border crossing is a chance to end up without data. This guide covers the two ways to solve that, what each country's networks are like, and which plan makes sense for which route.

Single-country or regional?

You have two options, and the right one depends on how your trip splits.

Single-country plans are cheaper per gigabyte and connect to the best networks in that country. If you're spending ten days in Vietnam and three in Singapore, buy a Vietnam plan and a small Singapore plan. You'll install two eSIMs and switch between them, which takes ten seconds in settings.

Regional plans cover many countries on one eSIM. Roamly's Asia plan covers 20 destinations including Thailand, Vietnam, Indonesia, Malaysia, Singapore, the Philippines and Cambodia, with 5GB for A$25.50 and 10GB for A$39.40 over 30 days. You install once and forget about borders.

The rule of thumb: two countries or fewer, go single-country. Three or more, or a route that's still changing, go regional.

Country by country

Thailand

Excellent 4G and 5G everywhere tourists go, including the islands. Coverage on Koh Phangan and Koh Tao is better than most Australian regional towns. Roamly's Thailand plans start at A$6.80 for 3GB, with 10GB for 30 days at A$14.30, which is the best value in the region. Grab is the app you'll live in; it works over data and takes foreign cards.

Vietnam

Strong coverage in Hanoi, Ho Chi Minh City, Da Nang and Hoi An on Viettel, Vinaphone and MobiFone, which is what Roamly's Vietnam plans connect to. Viettel has the widest rural reach, so Ha Giang loop and Sapa trekking are mostly covered on the roads. Plans start at A$8.00 for 3GB and A$21.30 for 10GB. Grab works in the cities; Xanh SM is the alternative.

Indonesia and Bali

Covered in detail in our Bali eSIM guide. Short version: good 4G across the south and Ubud, patchier on the Gilis and Nusa Penida, and plans from A$7.00. Gojek and Grab both work.

Malaysia

Kuala Lumpur, Penang and Langkawi are all well covered with 5G in KL. Borneo is fine in Kota Kinabalu and Kuching, patchy in the interior. Malaysia plans start at A$9.20 for 3GB.

Singapore

Wall-to-wall 5G. You'll never lose signal, including on the MRT. Most people only need a small plan for a stopover: 3GB is A$7.65.

Philippines

Manila, Cebu and Boracay have good 4G. Palawan and the smaller islands vary a lot by network, so manual network selection is worth knowing. Plans from A$10.10.

Worked examples

Two weeks in Thailand, three days in Singapore

Single-country. A 10GB Thailand plan (A$14.30) plus a 3GB Singapore plan (A$7.65). Total A$21.95, and you're on the best network in each country.

Bangkok, Hanoi, Hoi An, Bali over four weeks

Regional. A 10GB Asia plan at A$39.40 covers all four stops on one eSIM. Top up if you run low. Buying four single-country plans would cost more and mean four installs.

A month in Vietnam, moving slowly

Single-country. A 20GB Vietnam plan at A$38.50 gives you plenty of data on the networks with the best rural coverage.

Apps to set up before you fly

• Grab and Gojek. Create accounts at home with your Australian number. Some sign-up flows want an SMS code, which your Australian SIM will still receive overseas.

• Google Maps offline areas for each city. Navigation then barely touches your data.

• Google Translate with Thai, Vietnamese and Indonesian downloaded for offline use.

• Your bank's app with notifications on, so you see the card being tapped at a night market before you've left the stall.

Setting up

Install your plan on Wi-Fi at home before you fly, following the installation guide. On arrival in each country, make sure the eSIM is your mobile data line and data roaming is on for it. If you're using multiple single-country eSIMs, switch the data line as you cross borders.

See the Asia regional plan, or browse by country if your trip is staying put.