Some articles on this site contain affiliate links, meaning we may be compensated if you purchase a product or service after clicking on them. Read our full disclosure policy here.
There’s nothing quite like travelling in the United States. It’s a massive, incredibly diverse country. The non-stop action of New York City. The wide-open plains of Montana. Bubbling springs at Yellowstone, muscle-bound beaches in Miami, and much, much more.
For a country that leads the world in technology, though, the prepaid SIM card market for international visitors has long been surprisingly confusing, limited and expensive. With incompatible technologies between providers, locked phones, and post-paid plans the norm for locals, tourists have been poorly catered for.
Things have got slightly better in the last few years, although still a far cry from regions like South East Asia or even Western Europe. Still, you can now at least easily find a store, buy a SIM card that will work in your phone, pay a not-totally-unreasonable amount of money for a useful amount of calls, text and data, and get it all done in a few minutes. That’s a vast improvement.
There are four main cell service providers in the United States — but only two of them are of much interest to travellers.
Verizon (which has one of the largest networks) and Sprint used to only use CDMA technology that’s incompatible with almost any phone not sold by them. Both companies have, however, been rolling out GSM-based LTE service in recent years.
Note that most international phone models won’t get LTE service with any carrier, as the US uses different frequencies to most countries outside North America.
For Verizon, this means a small range of phones sold overseas (including recent iPhones) will now connect to its LTE network. Given that its prepaid service costs more than the competition, however, and many international phones still won’t work, it’s hard to recommend Verizon to international visitors unless you know your phone is compatible, and are travelling somewhere that only Verizon offers reliable coverage.
Sprint has the smallest network of the four carriers, and can’t offer voice service over LTE (so, no calls for anyone with a non-Sprint phone). There’s no reason for international visitors to consider using it.
Of the other two companies, AT&T has the largest (and often, most congested) network, offering coverage throughout most of the continental United States (map). It’s a big country, though. If you’re planning on road-tripping through lightly-populated states like Nebraska, Montana and a few others, you’ll still hit some very large dead spots.
T-Mobile has less coverage in rural areas (map), with particularly large gaps in Idaho, Nevada, Oregon, Montana, New Mexico and eastern California. On the upside, when you do have signal, data speeds will often be reasonably fast.
There are several resellers of service on both networks — and none are particularly great. Prices are typically only slightly less than buying direct from the provider, often with data speed limits, poor customer service and purchasing difficulties for overseas visitors without a local address or credit card.
With most of my trips to the US largely confined to the cities, coverage areas haven’t been a major problem with either provider. Pricing and data allowances have typically been quite similar between AT&T and T-Mobile, and in my experience, the knowledge and service levels of the instore staff have been much better with T-Mobile.
Note that both AT&T and T-Mobile use “4G’ to describe what the rest of the world knows as “HSPA+” or 3.5G. As a result, you’ll likely see 4G on your phone screen, but it’s not LTE!
Offering prepaid SIM cards at international airports doesn’t seem to have caught on in the US. I’ve flown into several in the country, and don’t recall seeing marked kiosks or signage at any of them. Fortunately, T-Mobile stores are quite common in large cities, and even smaller places should have at least one store.
I’ve bought SIMs in stores in Santa Monica in Los Angeles, and Seattle’s Capitol Hill. In both cases, I walked out with an activated SIM card in under ten minutes. It had cut-outs for both micro and nano sizes.
The process was simple — confirm you’ve got an unlocked phone, specify the plan you’d like, and hand over the money. You’ll get a receipt with your phone number printed on it.
It’s always worth putting the SIM in your phone and confirming it works straight away. I didn’t have any problems — mine took less than a minute to activate both times — but I’m always a little nervous when I don’t see the card working in my phone before leaving the store.
Can't be bothered with the hassle of buying a local SIM in the United States? OneSIM topped our international SIM card comparison.
It offers phones and SIM cards that work in 200 countries, have free incoming calls, save up to 85% on roaming fees, and can be sent out ahead of time to let you hit the ground running. Find out more here.
While you shouldn’t expect any real bargains on prepaid cell service in the US, prices do seem to be getting better for light to moderate use.
Note: for extra bonus confusion, you often can’t get the same deals in-store that you can online, with either company. Since most international visitors will be buying their SIM from a store, I’ve focused on those options — but if you have a US shipping address you can use, it’s worth checking out the online-only plans as well.
Unlimited, or at least large numbers of calls and texts are common on most plans. AT&T’s prepaid monthly smartphone plans started at $35 for 1GB of data or $45 for 6GB. T-Mobile charged $45 for 4GB of data, or $55/6GB.
If you’re in the country for three weeks or less, though, T-Mobile’s tourist package is the best value. For $30, you get 2GB of high-speed data (plus unlimited, slow data if you exceed that limit), plus 1000 minutes of domestic calls and 1000 domestic or international texts. That’s the plan I went with.
At both the AT&T and T-Mobile stores I visited, the SIM card itself was free. This isn’t always the case, however, so definitely check before committing.
Don’t forget, you’ll pay sales tax on top of the quoted price, ranging from nothing to nearly 10% depending on which state you’re in at the time.
Note: T-Mobile doesn’t offer any prepaid data-only plan instore. AT&T does — but only for tablets. If you happen to mention you’ll be using it in a phone, they won’t sell it to you! I’ve read reports of problems activating an AT&T data-only SIM in a phone as well, so don’t necessarily expect it to work if that’s what you want to do.
The T-Mobile tourist plan I purchased expires after 21 days, and can’t be renewed or added to.
For other plans, you can top-up your account online, using just your phone number and a credit or debit card. Since international cards work with this method, it’s probably the easiest way to do it.
Failing that, any T-Mobile store will be able to help you out, as well as authorised retailers. You can check locations here.
Get Us in Your Inbox
Get our regular email updates with the latest travel tech news, tips, and articles. We'll also send over a free 5000-word guide to get you started!
Coverage and Data Speeds
As mentioned above, T-Mobile coverage is good in most large towns and cities, but drops away in rural areas, with large dead zones in several states. Compare the service map to your intended destinations, and if you’re going to be spending significant time driving or staying in places without signal, consider AT&T instead.
“4G” speeds in Los Angeles, Seattle, Portland and elsewhere were all good, with strong signal both inside and outdoors. Voice calls were clear, and SMS delivery was reliable.