Mobile internet on the road settles almost everything: maps, ride-hailing apps, translation, banking. Travellers today have three options — roaming with your home carrier, a local SIM card, or an eSIM. Here's a calm look at what works where in Asia and when, with no brand promotion.
Three ways to get online
- Home carrier roaming: works instantly, but usually the most expensive option and capped on data.
- Local SIM card: bought at the airport or a phone shop, usually the cheapest data and a local number.
- eSIM: a digital SIM you activate through an app or QR code without visiting a shop — convenient if your phone supports it.
eSIM: who it suits
The appeal of eSIM is that you can buy and activate it in advance, back home, and switch it on the moment you land. You'll need a phone that supports eSIM (most modern models do, but older phones and some regional versions don't). Check this before your trip: if it's not supported, plan for a local SIM instead.
- Pro: no need to hunt for a shop or explain yourself in the local language.
- Pro: you can keep your home number active for banking SMS while running data through the eSIM.
- Con: usually data only, with no local number for calls.
- Con: the price per gigabyte is often a bit higher than a local physical SIM.
Country by country
In Thailand and the UAE, buying a local SIM at the airport is simple, and the internet is fast and stable. On Bali (Indonesia), coverage is good in the tourist areas but can drop off further inland and in the hills. In Vietnam, mobile internet is cheap and fast in the cities. In Sri Lanka, it's best to get a local SIM from a major carrier — coverage outside tourist areas is patchy.
What to choose by default (approximate, check before you travel)
| Country | A sensible default option |
|---|---|
| Thailand | Local SIM at the airport or eSIM |
| Bali (Indonesia) | Local SIM from a major carrier |
| Vietnam | Local SIM or eSIM, internet is cheap |
| UAE | Local SIM at the airport or eSIM |
| Sri Lanka | Local SIM from a major carrier |
Keep your home number for banking SMS, and put your data traffic on a local SIM or eSIM.
A short pre-flight checklist
- Check whether your phone supports eSIM.
- Make sure your phone isn't locked to a single carrier.
- Save offline maps of the city in advance, in case the internet drops.
- Keep your home number active for incoming SMS from your bank.
- Note down how to turn off mobile roaming, so you don't end up with an extra bill.
* Carrier rates, coverage and terms change. Check current details before you buy.
