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Using your phone in Thailand: roaming or a travel eSIM?

· Telroo

Short answer: for most trips to Thailand you choose between your Australian carrier's daily roaming and a prepaid travel eSIM. Roaming keeps calls and texts on your own number for a daily fee. A travel eSIM is a separate, data-only line paid for once, and it needs an eSIM-capable, carrier-unlocked phone. Many travellers combine the two: the eSIM for data, with the Australian line left on for texts and its data roaming turned off.

There is no single right answer, so this article sets out what to compare rather than ranking options. The Thailand eSIM guide has the current plan table if you are ready to choose a plan.

What Australian carriers offer in Thailand

All three main carriers list Thailand as an eligible roaming destination. From their own roaming pages, checked on 24 October 2026:

Carrier Option and zone What the page says
Telstra International Roaming Day Pass, Zone 2 (includes Thailand) $10 per day with 2GB of data a day and unlimited standard calls and SMS
Optus Optus Daily Roaming, Zone 1 (includes Thailand) $5 for 5GB to use within 24 hours, with unlimited standard talk and text, on Choice Plus, Plus Family and Plus Promo plans; if you use the 5GB within the 24 hours, another 5GB is added for $5
Vodafone $5 Roaming (Thailand listed as a $5 Roaming destination) $5 extra per day to use your plan's included data, calls and texts, on eligible plans; additional data after that is charged at $5/GB; up to 90 days a calendar year

These are post-paid options. Prepaid services, and some post-paid plans, work differently, so check what applies to your plan.

How a roaming day starts

Telstra's page says Day Pass charges apply on days your service is used overseas to make or receive calls, send an SMS or use data, including background data. Receiving an SMS does not trigger a charge. It also says a Day Pass can take up to 2 hours to activate, so turn it on before you fly. Optus says Daily Roaming is activated automatically in eligible destinations, and Vodafone says $5 Roaming activates automatically when you turn on your phone in an eligible destination.

The practical point: if data roaming stays on for your Australian line, apps refreshing in the background can start a paid day. If you are using a travel eSIM for data, turn data roaming off on the Australian line.

For a two-week trip, multiply your carrier's daily fee by the days you expect to use the service and compare that with a single prepaid plan for the trip. Travel eSIM or international roaming walks through that calculation with an example.

What to compare in a Thailand travel eSIM

Prices are easy to compare. These details are less visible but matter as much.

  1. Networks. On 24 October 2026 both Telroo Thailand plans listed AIS 5G and DTAC 5G. Coverage still depends on where you are; islands, national parks and long road transfers can differ from Bangkok.
  2. Total or daily data. A total allowance (for example, a set number of GB for 30 days) can be used unevenly: more on a travel day, less by the pool. A daily plan gives a fresh high-speed allowance every 24 hours, but unused data does not carry over.
  3. What happens after a daily allowance. On the Thailand Unlimited eSIM, data continues at a reduced speed once the daily high-speed allowance is used: 1 Mbps on the 1GB and 3GB a day options, 384 Kbps on the 5GB and 10GB a day options, until it resets. "Unlimited" here means you are not cut off, not that speed stays the same.
  4. When validity starts. Some plans start when the eSIM first connects to a network in the destination; others can start at installation. Read the selected plan's activation instructions before you install.
  5. Top-ups. Top up eligible plans from your order page, subject to eligibility. For eligible Daily plans, top-ups extend the number of days; they do not increase the daily high-speed allowance or remove today’s speed reduction. Keep your existing eSIM installed.
  6. Hotspot. Both plans allow it. Sharing uses the same allowance.
  7. Data routing. The fixed-data Thailand plan lists Singapore as its data exit country. Some websites may show Singapore results while you are in Thailand; maps that use your phone's location are not affected. Read what a data exit country means.

Telroo sells these plans; this list describes what they include and is not an independent comparison or a coverage test.

Fixed data or a daily plan for 7, 10 or 14 days?

A fixed plan suits you if you want one budget for the whole trip and your use varies from day to day. A daily plan suits you if you want to stop thinking about data and use a similar amount every day, such as maps, rides and video calls home each evening.

Rather than repeat numbers here, the Thailand guide's plan table divides each fixed plan by trip length and lists the daily options, and how much travel data do I need helps you estimate from your own phone's use.

Keeping your Australian number for texts and calls

A Telroo travel eSIM has no Thai number, and it does not replace your Australian one. On a dual-SIM phone, set the travel eSIM for mobile data, turn off data roaming on your Australian line, and leave the line switched on if you want bank codes and other texts to arrive. Whether receiving a call or text costs anything depends on your carrier.

The iPhone and Samsung settings are in keeping your Australian number while using a travel eSIM.

Before you land: arrival card and phone set-up

Smartraveller's Thailand page (updated 15 October 2026, checked 24 October 2026) has several points that involve your phone:

  • Thailand Digital Arrival Card (TDAC). You must complete it online through the Thai Immigration Bureau website within 3 days before arriving. It is free; Smartraveller warns about fake websites charging a fee. Do it at home on Wi-Fi rather than relying on a connection at the airport.
  • Tourist Police. Call 1155 for the tourist police, or contact them through the Thailand Tourist Police App, which Smartraveller describes as being for tourists without a Thai SIM card. If you use a data-only eSIM, consider installing the app before you go.
  • Emergency alerts. Smartraveller suggests setting your phone to allow emergency alerts from the Thai Department of Disaster Prevention and Mitigation.
  • Wet season. From May to November, floods and severe weather can disrupt services, including phone services. Save tickets and bookings offline before you travel in that period.
  • Public Wi-Fi. Smartraveller warns that devices and data can be stolen when using public Wi-Fi.

If you would rather use a Thai SIM

A local SIM or eSIM gives you a Thai number, which some travellers want for calling local businesses. Requirements, such as the identification asked for at purchase, are set by the provider, so ask them before you buy. With a single-SIM phone, a local physical SIM also takes your Australian number out of the phone until you swap back.

Common questions

Does a Thailand travel eSIM include a Thai phone number? No. Telroo plans are data-only, with no number, standard calls or SMS. WhatsApp, LINE and other apps work over data.

Is a daily plan the same as unlimited full-speed data? No. After the daily high-speed allowance, speed is reduced until the allowance resets.

Can I keep using my Telstra, Optus or Vodafone number? Yes. Keep the Australian SIM in the phone and switched on. Turn off its data roaming if you do not want roaming data charges.

Should I install the eSIM before I fly? If the plan's instructions allow it, yes, on reliable Wi-Fi. The installation guide explains each step.

What if the eSIM does not connect after landing? Check that the Thailand line is selected for mobile data and that roaming is on for that line, then follow the troubleshooting checklist before deleting anything, or contact us.

See plans

Sources and last checked

Checked 24 October 2026. Carrier terms and prices change; check the carrier's page before you travel.

  • Telstra, International Roaming: Day Pass zones, prices and when a day is charged.
  • Optus, International Roaming: Optus Daily Roaming, Zone 1 destinations, eligible plans.
  • Vodafone, International Roaming: $5 Roaming terms and destination list.
  • Smartraveller, Thailand travel advice (updated 15 October 2026): TDAC, tourist police and app, emergency alerts, wet season, public Wi-Fi.
  • Telroo product pages linked above: networks, daily speed limits, hotspot and data exit country.

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