If you're traveling through Southeast Asia, combining Thailand and Vietnam—and perhaps Cambodia or Laos—buying an eSIM for each country can be a hassle with QR codes and activations. In this guide, we compare options to help you choose the best eSIM for Thailand and Vietnam based on your itinerary, trip duration, and actual data usage.
In summary: For a trip that combines only Thailand and Vietnam, the most suitable option currently is an eSIM per country: one for each destination, activated before you leave. If your route includes Singapore or Malaysia, then a regional eSIM makes sense for that segment. Estimate your daily data usage and decide based on how many countries you'll visit.
The quick answer
If your itinerary is only Thailand and Vietnam, the most sensible approach right now is to get a country-specific eSIM: one for Thailand and one for Vietnam, both activated before you leave home. Currently, there isn't a regional eSIM that exactly covers these two countries without including unnecessary coverage; if your itinerary adds Singapore or Malaysia, then a regional eSIM for that segment makes sense. For the Thai leg, the Thailand eSIM allows you to use data in Bangkok, Chiang Mai, or the southern islands as soon as you land.
The advantage of installing both eSIMs before you leave is that everything is ready: you activate the Thailand data plan upon landing in Bangkok or Phuket, and when you cross into Vietnam—by plane or land from Cambodia—you switch data plans from your phone settings in less than a minute, without searching for SIM card shops at the airport or struggling with a new QR code late at night.
Practical rule: For Thailand + Vietnam only, a country-specific eSIM is currently the most suitable option. If your route includes Singapore or Malaysia, then it's worth considering a regional eSIM for that part of the trip.
Country-specific eSIM vs. regional Asia eSIM
Country-specific eSIMs are usually a bit cheaper per gigabyte and are the most direct option if your route is only Thailand and Vietnam with no other stops. Regional eSIMs make more sense when your itinerary includes other Southeast Asian countries: for example, if you enter through Singapore, pass through Malaysia, and end up in Thailand, the Singapore, Malaysia, and Thailand eSIM covers those three segments with a single installation. For Vietnam, you'll still need its own eSIM, as no regional eSIM currently covers it along with Thailand.
So, if your plan is exclusively Thailand and Vietnam, don't look for a regional eSIM that "covers everything": plan your trip with the Thailand eSIM for the first leg and address Vietnam with its own eSIM when you reach that part of the route. It's more data-efficient, and you won't overpay for coverage in countries you won't visit. If you also enter via Cambodia or Laos by land, note that neither of the individual eSIMs will cover that intermediate segment: in that case, it's worth having some backup Wi-Fi (from the bus or hostel is usually sufficient) until you reach the next country.
Real coverage in Thailand and Vietnam
4G/5G coverage in cities and tourist areas in both countries is excellent. In Thailand, you'll have no problem using data in Bangkok, Chiang Mai, Phuket, and the most visited islands; in Vietnam, in Hanoi, Ho Chi Minh, Da Nang, and Hoi An, the signal is strong. It drops in small islands, mountain treks, and long bus journeys through rural areas, which is normal with any operator.
Both the Thailand eSIM and the Vietnam eSIM rely on the networks of the leading local operators in each country, so you connect to the best available antenna in each area without doing anything. In islands like Koh Tao or Ninh Binh, there might be spots with weak signal: download offline maps before you go. If you want to delve deeper by destination, we have dedicated guides to internet in Thailand and internet in Vietnam with city-specific coverage details.
How many GB you need for your trip
It depends on your usage, but the average Southeast Asia traveler uses more data than they think: maps all day, Grab for transportation, photos and videos to the cloud, and video calls home. Moderate usage is around 1-1.5 GB per day; if you upload many stories or stream, it goes up to 2 GB or more.
- Light use (maps, messaging, some social media): 500 MB - 1 GB per day.
- Medium use (above + photos, Grab, some video): 1-1.5 GB per day.
- Intensive use (streaming, many stories, long video calls): 2 GB or more per day.
For two weeks of medium use, estimate about 15-20 GB or opt for a large data plan. If you prefer to make every gigabyte count, this guide on how to save data on your travel eSIM might interest you. And a tip: in hotels and cafes in Southeast Asia, there's Wi-Fi everywhere, so you can save your eSIM data for when you're out and about.
Plan comparison by days
As a rough guide, here's how plans align with common Thailand and Vietnam itineraries. Exact prices vary, but the logic of days and gigabytes will help you decide.
| Trip Type | Days | Estimated Data | Recommendation |
|---|---|---|---|
| Bangkok Getaway | 4-5 days | 5-8 GB | Thailand eSIM |
| Vietnam Only | 10-12 days | 10-15 GB | Vietnam eSIM |
| Thailand + Vietnam | 14 days | 15-20 GB | Thailand eSIM + Vietnam eSIM |
| Route with Singapore or Malaysia | 21-30 days | 20-30 GB | Regional Singapore-Malaysia-Thailand eSIM + Vietnam eSIM |
If your route includes Singapore or Malaysia in addition to Thailand, the balance shifts towards a regional eSIM for that segment; for Vietnam, you'll always need its own eSIM. To better understand the differences compared to other connection options, check out this comparison between international SIM cards and eSIMs.
How to choose based on your travel style
The "best" plan doesn't exist in a vacuum: it depends on your route. A short, single-destination trip calls for a country-specific eSIM; a long journey across several destinations requires evaluating a regional eSIM for segments where it's available. And there are factors beyond price that make a difference when something goes wrong 10,000 km from home: ease of installation, the ability to top up on the fly, and support in your language. If you're debating whether to stick with your home operator's roaming or switch to a local eSIM, this comparison of eSIM vs. roaming clarifies the reason for the switch: price and speed, especially in Vietnam, where European roaming tends to be slow and expensive.
For backpackers who string together Thailand, Vietnam, and more, convenience is key: install each eSIM before leaving home and forget about it at the airport. And if you're wondering whether to visit Thailand alone or extend to Cambodia by land, remember that this border segment is not covered by either the Thailand eSIM or the Vietnam eSIM: arrive with data until the border and reactivate the next eSIM as soon as you have coverage in the new country. Prioritize quick activation too: landing, turning on your phone, and getting online without searching for Wi-Fi is what separates a good first day from an afternoon lost looking for a physical SIM card shop at Suvarnabhumi or Tan Son Nhat airport.
Myths and what almost no one tells you
There are several ideas circulating about eSIMs in Southeast Asia that don't quite hold up when you test them on the ground. Here are the ones that most confuse first-time travelers to Thailand and Vietnam.
- "A regional eSIM is always more cost-effective." False if your route is only Thailand and Vietnam: you pay for coverage in countries you won't visit, and currently, there is no regional eSIM that covers exactly these two destinations. A regional eSIM only pays off when you truly cross three or more borders.
- "In Vietnam, my Spanish operator's roaming is fine." Technically, it works, but the cost skyrockets as soon as you leave the European flat rate, and the speed is usually far behind a local Vietnamese eSIM, especially outside Hanoi and Ho Chi Minh.
- "I need to activate the eSIM before leaving Spain." You don't need to activate it, just install it (scan the QR and save the profile). You activate data upon landing so you don't waste validity days while still at home.
- "If I have the Thailand eSIM installed, it will still work in Vietnam." No: each country-specific eSIM works with that country's operators. As soon as you cross into Vietnam, you need to switch your data plan to the Vietnamese eSIM in your phone settings, or you'll lose connection until you do.
- "The more gigabytes, the better, just in case." Overestimating data consumption is one of the most common mistakes when buying for the first time. With Wi-Fi available in most accommodations and cafes in Southeast Asia, a medium-sized data plan calculated for your actual days out and about is almost always enough, not a "just in case" plan.
- "On Thai islands, coverage is as good as in Bangkok." Not always. On small islands like Koh Phangan or Koh Tao, the signal can drop in coves far from the main village; download offline maps before moving around the island, not when you're already lost looking for your bungalow.
Frequently asked questions
Do I need a different eSIM when I go from Thailand to Vietnam?
Yes. The Thailand eSIM works with Thai operators and stops working once you cross into Vietnam. Install the Vietnamese eSIM before leaving home, and upon landing in Hanoi or Ho Chi Minh, switch the active data line from your phone's settings: you'll have a connection again in a couple of minutes.
Is it cheaper to buy a country-specific eSIM or a regional one?
If you're only traveling to Thailand and Vietnam, an individual eSIM for each country is usually the most suitable option because there isn't a regional eSIM that covers exactly these two destinations. If your route includes Singapore or Malaysia, then the regional eSIM pays off: you save the cost and time of multiple activations for that segment.
How many gigabytes do I need for two weeks in Southeast Asia?
For average use (maps, Grab, messaging, photos, and some video), calculate 1-1.5 GB per day, which means about 15-20 GB for two weeks. Since there's plenty of Wi-Fi in hotels and cafes, you can save your eSIM data for when you're out and about and feel more at ease.
Does the eSIM cover land borders between countries?
It depends on the plan. The regional eSIM for Singapore, Malaysia, and Thailand automatically reconnects when crossing between these three countries by land. Between Thailand and Vietnam, or if you enter via Cambodia or Laos, there is no continuous coverage: you'll be without data in that intermediate stretch until you activate the eSIM of the next country.
Can I make regular calls with the Southeast Asia eSIM?
The eSIM is for data, so you can make calls and video calls via WhatsApp, Telegram, or similar without a problem. For traditional phone calls, you still use your home number through your regular SIM, or use voice-over-internet apps. For travel, data and messaging apps are more than enough.
What if my phone doesn't support eSIM?
You need an unlocked phone compatible with eSIM, which is common in mid-to-high-end models from recent years. If your phone only supports physical SIMs, you'll have to rely on a local SIM at the airport or your operator's roaming, with the cost and inconvenience that usually entails.
Conclusion
For Thailand and Vietnam on the same trip, the most suitable combination today is a Thailand eSIM for the first leg and its Vietnamese equivalent for the second, each installed before leaving home. If your route includes Singapore or Malaysia, then the regional eSIM for those three countries comes into play. Estimate your actual daily data usage, see how many countries you're actually visiting, and choose without overcomplicating things: arriving with active data is what makes the difference on the first day of your trip.
