Unlimited data eSIM for Thailand: what "unlimited" really means and what it costs

Almost every eSIM brand sells an "unlimited" plan for Thailand. The word means very different things depending on whose terms you read. Some give you a few GB a day at full speed and then slow you to roughly 1 Mbps until midnight. Others promise no cap but reserve the right to reduce speed under fair use.

This page explains the difference in plain terms, shows exactly what a VoaSim unlimited eSIM for Thailand costs per day, and gives you a short checklist to read any brand's fine print before you pay.

Truly unlimited vs "unlimited with a daily cap"

There are three common models sold as unlimited. Knowing which one you bought matters more in Thailand than in most places, because you will be streaming maps, uploading photos and video calling home from islands with no Wi-Fi worth using.

• Daily high-speed allowance: you get a set amount of fast data every 24 hours, then the connection drops to a slow speed for the rest of the day. Airalo publishes 3 GB/day of high-speed data on its unlimited plans by default; Nomad publishes about 2 GB/day on most plans and states openly that these plans do not offer unrestricted high-speed data.
• No published cap, but a fair-use clause: Holafly does not publish a daily cap but says operators may reduce speed under fair use for up to a day.
• Truly unlimited: VoaSim sets no data cap, applies no throttling and has no hidden fair-use policy. You use what you use.

None of these is dishonest. But if you only need maps and messaging, a capped plan can be cheaper. If you stream or work from the road, read on.

How much an unlimited Thailand eSIM costs with VoaSim

Price set by destination and trip length, for Thailand and for every other destination VoaSim covers. Today's table includes the current 15% promo:

Trips of 1 to 4 days pay the 5-day package. One eSIM covers up to 90 days maximum. Buying a second eSIM in the same order gets an extra 10% off, which is the cheapest way for a couple to travel. Check your exact dates in the price simulator.

Coverage in Bangkok, Phuket, Chiang Mai and the islands

The eSIM connects automatically to local Thai networks — AIS, True and Dtac — on 4G and, where the network supports it, 5G. You do not pick an operator or type anything in; the phone registers on whatever signal is strongest at the moment.

In practice, Bangkok and the big resort areas are well covered. Chiang Mai, Krabi, Phuket town and Koh Samui are fine for maps, Grab rides, video calls and uploading photos. On long-tail boat trips and island-hopping tours, signal comes and goes once you are far from shore — that is the network's reach, not the eSIM. Same logic applies to cruises: the eSIM works in port, not out at sea.

If you are also stopping in Singapore, Vietnam or Japan on the same trip, each country needs its own eSIM at its own price. See all destinations.

Today's prices

Today's promo prices (15% off). Each destination has its own price. 2 to 4 eSIMs in the same order: 10% extra off. Trips of 1-4 days use the 5-day package.

A checklist for reading any brand's unlimited terms

Before you buy from anyone, including us, run through these five questions. The answers are always somewhere in the terms page or the help center.

1. Is there a daily high-speed allowance? If yes, how many GB and what speed comes after it.
2. Is there a fair-use clause? Some brands with no published cap still allow operators to slow you down.
3. Does hotspot count toward the cap? Airalo says tethering counts against the same allowance; Holafly limits hotspot to 1 GB/day. VoaSim does not allow hotspot at all — share the connection and the local carrier may block the line.
4. When do the days start? On VoaSim, counting starts at the first connection to a network in Thailand, not at purchase.
5. What happens if it does not connect? VoaSim refunds 100% if support cannot fix it.

The VoaSim eSIM Price Index tracks unlimited eSIMs daily and separates plans with and without a daily high-speed cap, with the method published.

Setting it up before you fly to Thailand

The QR code lands in your email within minutes of payment (plus a WhatsApp heads-up if you left a number at checkout). Install it at home, on Wi-Fi, while you still have help available.

• Check compatibility first: iPhone XR or newer, Galaxy S20 or newer, Pixel 3 or newer, and most phones from 2020 on. Universal test: dial *#06# — if an EID appears, your phone has eSIM. Carrier-locked phones must be unlocked.
• Install the eSIM but keep that line switched off until you land in Bangkok or Phuket. On Android, do not turn on the eSIM's data before the trip, or the clock starts early.
• Keep your physical SIM in the phone. Your number and WhatsApp stay yours. Just turn off your home carrier's data roaming.
• Landed and no signal? The free eSIM Rescue tool diagnoses any brand's eSIM.

Payment is by international credit or debit card in USD through Stripe, with an invoice by email.

When another option may suit you better

We would rather you buy the right thing than the wrong thing from us.

If you need to tether a laptop or a second phone in Thailand, a VoaSim eSIM is the wrong tool — hotspot is not allowed, and sharing can get the line blocked by the local operator. Look at brands that permit tethering within a cap, or buy a second VoaSim eSIM for your travel partner with the extra 10% off.

If your trip is three weeks of maps, messaging and the occasional podcast, a capped plan sold by GB may cost less than unlimited. Do the math honestly.

If you want a local Thai phone number for deliveries or bookings, a physical SIM from an airport shop is the answer — bring your passport, expect registration and lose your home SIM slot for the trip. For a straight comparison of approaches, see our comparison hub and the roaming guide.

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