The Best eSIM for Thailand, Mexico and Portugal in 2026

Thailand, Mexico and Portugal are the three countries we get asked about more than any others in 2026. They sit in three different time zones, on three different continents, and they all have one thing in common: the first hour after you land is much easier with data that already works.

This is the short, no-nonsense version of which eSIM to buy for each country, what they actually cost, where they fall short, and the exact plan we'd put on our own phone before boarding.

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TL;DR — the plan we'd buy for each country

• Thailand (2 weeks): Airalo "Sabai" 5 GB / 30 days — around $9–11. Strong coverage in Bangkok, Chiang Mai and the islands.
• Mexico (2 weeks): Airalo "Mexico" 5 GB / 30 days — around $11–13. Reliable across CDMX, Cancún, Tulum and Oaxaca.
• Portugal (2 weeks): Airalo "Eurolink" Europe regional plan — around $13–18 for 5 GB / 30 days, and it keeps working in Spain, France and 38 other countries.

If you only read one section: buy the regional plan for Portugal, the country-specific plan for the other two, and skip your home carrier's roaming. The math is not close.

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Thailand: which eSIM actually works on the islands

Thailand has three big mobile networks — AIS, TrueMove H and DTAC. AIS is the one nomads keep coming back to: it has the best coverage in Chiang Mai's old city, on Koh Phangan during full moon weekends, and in the parts of Phuket where the other two start to wobble.

Most eSIM apps quietly route you onto AIS or TrueMove. Airalo's "Sabai" plan does both, with automatic switching. Real-world speeds we've seen:

• Bangkok (Sukhumvit, Ari, Ekkamai): 40–120 Mbps down, plenty for video calls.
• Chiang Mai (Nimman, Old City): 25–80 Mbps. Drops in some cafés — switch to café Wi-Fi for uploads.
• Koh Phangan / Koh Tao: 8–30 Mbps, occasional 3G fallback inland.

What to buy: 5 GB / 30 days for a typical 2-week trip. Stretch to 10 GB if you're working remotely without home Wi-Fi. What to avoid: the in-airport plastic SIM kiosks. They're 2–3x the eSIM price and you'll waste 25 minutes in a queue at 1 a.m.

If Thailand is on the shortlist, our Bangkok guide and Chiang Mai guide cover where to base yourself once the data is sorted.

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Mexico: don't land without an eSIM

Mexico is the country where having data on landing matters most, because the airport-to-apartment trip in CDMX, Cancún or Tulum almost always involves an Uber or Didi — and both require an active data connection from the curb. The taxi mafia outside Mexican airports is a real thing and they will quote you 4–6x the Uber price.

The dominant networks are Telcel (best coverage), AT&T Mexico and Movistar. Airalo's "Mexico" plan rides on Telcel, which is what you want.

Real-world speeds:

• Mexico City (Roma, Condesa, Polanco): 30–90 Mbps. Solid for everything except large uploads.
• Cancún / Tulum: 20–60 Mbps in town, patchy on the beach road south of Tulum.
• Oaxaca City: 15–45 Mbps. Mountains around it are where Telcel pulls ahead.

What to buy: 5 GB / 30 days for a 2-week trip, 10 GB / 30 days if you're working full days. One thing to know: WhatsApp is how Mexico runs — Airbnb hosts, dive shops, restaurants, drivers. Having data before you leave the airport means you can confirm the apartment address without standing in a Starbucks at midnight.

Our Mexico City guide and Tulum guide go deeper on neighborhoods once you're set up.

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Portugal: buy the regional plan, not the country plan

This is the one place where the obvious choice is wrong. A Portugal-only eSIM is fine, but a Europe regional eSIM usually costs only $2–4 more and covers the entire Schengen area. Almost everyone who flies to Lisbon ends up in Porto, Sevilla, Madrid or Paris within the same trip.

Portugal's networks (MEO, Vodafone PT, NOS) are all fast, with MEO leading in Lisbon and Vodafone leading in the Algarve. Airalo's Eurolink rotates between local networks automatically.

Real-world speeds:

• Lisbon (Príncipe Real, Alfama, Marvila): 50–150 Mbps. Genuinely fast.
• Porto: 40–120 Mbps. Reliable everywhere except the older parts of Ribeira.
• Algarve / Madeira: 25–80 Mbps. Madeira is patchy on the north coast.

What to buy: 5 GB / 30 days Eurolink for a 2-week Portugal trip, 10 GB / 30 days if you're doing Lisbon → Porto → Sevilla → Madrid.

If Portugal is the anchor, our Lisbon guide and Porto guide are where to start.

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How to install an eSIM before you fly (5 minutes)

1. Buy the plan on the Airalo app while still on home Wi-Fi.
2. Install the eSIM profile when prompted — it's a single tap on iPhone, two taps on most Androids.
3. Label it (e.g. "Thailand — Airalo") so you can spot it in settings.
4. Do not activate it yet. Most plans start counting from first connection, not from install.
5. On landing, turn off your home SIM's data, switch the data line to the Airalo eSIM, and toggle data roaming on for that line only.

The whole thing takes longer to read than to do. The Airalo app handles all of it.

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What about Holafly, Saily, Nomad, Maya?

They all work. Honest answer: for Thailand, Mexico and Portugal in 2026, the price/coverage delta between Airalo and the rest is small enough that we default to one app instead of juggling four. If you already have an account elsewhere, keep using it. If you don't, Airalo is the simplest single answer for all three countries.

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Keep planning

Pair this with the longer travel SIM vs eSIM guide, and once data is sorted, our travel insurance guide is what we'd read next. For the rest of the trip, the Bangkok, Mexico City and Lisbon city guides cover the on-the-ground specifics.