International SIM card: a roaming SIM, a local SIM or a travel eSIM?

What is an international SIM card?

An international SIM card is any SIM you use to get mobile service outside your home country, and the phrase covers three quite different products. One is a roaming SIM sold to work across many countries at once. One is a local prepaid SIM, bought in the country you land in. The third is a travel eSIM, the same idea with no card, bought online before you go. Your home carrier's roaming pass is a fourth option that needs no new SIM at all.

They're priced very differently, and the cheapest depends on where you're going. Prices below are the sellers' own, read off their sites in August 2026 and held in our country guides, and the carrier figures come from our international roaming plans page, read on 9 November 2026.

The roaming kind: one card for many countries

This is what "international SIM card" meant before eSIM. A company sells you a single plastic card, usually by post, that roams onto partner networks in dozens or hundreds of countries. You keep it in a drawer between trips and top it up.

We don't track any of these, and we won't quote prices we can't check. If you're comparing them, look for four things: the rate per megabyte or gigabyte in each country, which countries sit in which price zone, how long unused credit lasts, and whether the card gives you a phone number or data only. The weakness is the same as any roaming product: you're a visitor on someone else's network, and you pay for the privilege.

The eSIM version of the same idea is a global plan, and two of the brands we cover sell one. Nomad's global eSIM lists 123 countries, in sizes from 1 GB to 20 GB, and slows to 512 kbps once a daily high-speed allowance runs out; Airalo's is called Discover Global. Our Nomad global eSIM and Airalo global eSIM pages cover what each says. Neither is the cheap option for a single country, and we hold no verified price for either.

When does a local SIM bought on arrival win?

More often than eSIM sellers would like. The last column of our cheapest eSIM table is the typical price of a local prepaid SIM at the airport, and in a good number of countries it undercuts every eSIM we track:

One honest caveat. We know what those SIMs cost but not, in most cases, how much data comes with them, so this isn't a like-for-like table. A $7 card in Vietnam may well beat a $39 eSIM for a two-week trip. We can't prove it does.

What the local SIM reliably gives you is a named network. In Vietnam, our guide points to Viettel for the Ha Giang Loop, Sapa and Ha Long Bay, and no eSIM seller in our data is confirmed on it. In Japan, NTT Docomo has the widest rural and island coverage, and no travel eSIM we track is sold as a Docomo product. If the network matters, buy the network.

The cost is time and paperwork. Japan and Vietnam want a passport. The queue at a carrier desk after a few long-haul arrivals can eat an hour.

Prepaid SIM cards for tourists in the USA

The US is the biggest single search behind this page, so it gets its own answer. The country asks for no ID to buy a prepaid SIM. You walk into a carrier store or an airport shop, pay about $20, and leave connected. Easy paperwork, then. The price is the catch.

Against that, Airalo's 10 GB for 30 days was $22.50 when we read its site, and its 50 GB for 30 days was $42, which is the best US rate per gigabyte we hold, at $0.84. Saily's 1 GB for 7 days was $3.99 for a stopover.

The reason to buy the plastic card anyway is the network. Our USA guide found Verizon is the one for rural road trips and national parks, and no travel eSIM we track is confirmed to run on it. For New York, Chicago or Las Vegas, that doesn't matter; for Utah, it does.

One thing to check if you're a visitor: your phone must be unlocked. If you're an American going the other way, note that iPhone 14 models and later bought in the US have no SIM tray, so a local plastic SIM abroad isn't an option on them.

Travel SIM cards for Europe

Start with whether you need one. If your normal SIM is from an EU or EEA country, roam-like-at-home already covers you across the bloc, subject to your operator's fair-use policy. Buying anything on top is paying twice.

For everyone else, Europe is the cheapest region we cover. Every one of the 34 European countries we hold sits under $1 a gigabyte on its best verified plan, from Airalo's 50 GB at $29 in Austria upwards. Local SIMs at the airport run from about $8 in Poland to about $18 in Spain and Italy.

One quirk. A local SIM bought in one EU country is an EU SIM, so roam-like-at-home can apply to it elsewhere in the EU too. Operators set fair-use terms on that, so read them before you count on one Italian card carrying you to Lisbon. Our best eSIM for Europe page has the country-by-country floors.

Tourist SIM cards in Japan

Japan requires a passport or ID for SIM registration, and an airport SIM costs about $12 at Narita, Haneda or Kansai. Nomad's 10 GB for 30 days was $16 on its site, and its 50 GB for 30 days was $35, which is $0.70 a gigabyte and less than half what anyone else charges there.

For Tokyo, Kyoto and Osaka, we'd take the eSIM and skip the counter. For Hokkaido, the Alps or the smaller islands, the network decides it, and the Japan guide explains why that points to a local Docomo SIM.

Is there an international SIM card with unlimited data?

Yes, mostly as eSIMs. In Japan, Holafly's unlimited plan was $27.50 for 7 days; in the United States, Airalo sold 7 unlimited days for $25. Most unlimited plans carry a fair-use limit that isn't in the headline. Unlimited data eSIM compares them, and our cheapest eSIM ranking leaves them out because a plan with no allowance has no cost per gigabyte.

What about your own carrier's roaming?

It's the simplest option and almost always the dearest for data. AT&T's International Day Pass and Verizon's TravelPass are each $12 a day in most countries, so a ten-day trip comes to $120 for one line. T-Mobile is the exception worth checking: many of its plans include some roaming already. The international roaming plans page sets each against a travel eSIM.

What we'd buy

For a city trip on an unlocked phone with eSIM, a travel eSIM bought before you fly, sized up rather than down, since the big plans are almost always cheaper per gigabyte. For a trip where the network matters, or to a country where the airport SIM costs a few dollars, the local SIM, with your passport ready. A roaming SIM that covers many countries is for people who cross a lot of borders and have a phone that can't take an eSIM. Check first whether yours can: eSIM compatible phones.

Nobody pays us when you buy a local SIM. How this site makes money explains why we say so anyway.