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How to Buy, Activate and Set Up a US SIM Card or eSIM as a Visitor

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Last verified: 1 November 2026. We read the provider and maker pages on this date. We have not bought or activated any plan ourselves, so this guide says "not tested" where that matters.

The six steps.

  1. Check that your phone is unlocked.
  2. Check that it supports eSIM (or has a SIM tray), and that its model has the right bands.
  3. Pick a path: travel eSIM before you fly, carrier visitor eSIM after you land, or a store.
  4. Install the eSIM on Wi-Fi, or put in the SIM.
  5. Set the new line for mobile data. Turn Data Roaming on for that line only.
  6. Set a data warning, then test a map.

Some US products can only be bought after you land. T-Mobile's U.S. Pass is one of them. Jump to the path chooser. For prices, see which option is cheapest for your trip length. For plan fine print, see what each plan's fine print means.

Disclosure. Some links on this page are affiliate links. If you buy through them, prepayzo.com may earn a commission at no extra cost to you. We rank options by trip-length fit and total cost, we list downsides for every option (including the ones that pay us), and we include options that pay us nothing. Prices were checked on the date shown at the top of this page and can change.

Four terms used on this page. Premium data: data at top priority. Deprioritisation: after your premium data, you may be slower than other users when the cell is busy. Hard throttle: your speed drops to a low fixed level after a cap, for example 128 kbps. Fair-use policy: a rule that lets a provider limit "unlimited" data, often per day. See the fine-print guide.

Step 1: Check that your phone can do this

Do these checks at home, before you buy anything. Work through them in order.

CheckHowIf it fails
Not reported lost, stolen or fraud-flaggedAT&T's guides name stolenphonechecker.org for this checkContact your carrier before you buy anything
UnlockediPhone: Settings > General > About > Carrier Lock. It should say "No SIM restrictions"Ask your home carrier to unlock it. It can take days
eSIM supportiPhone XS, XS Max, XR or later. Android: check the maker's spec page for your exact modelUse a physical SIM (the phone still must be unlocked), or Wi-Fi only
Dual SIMNeeded for AT&T's pass: the phone must be dual-SIM enabled with an open eSIM slotAT&T's pass is not an option
BandsLook up your exact model number on the maker's spec pageExpect weaker coverage on some networks
IMEIDial *#06#. Use T-Mobile's IMEI checker. For AT&T, look at its approved-device listPick another network or a travel eSIM
VoLTET-Mobile asks you to check whether the phone supports VoLTE and Extended Range LTECalls may fail while data works. Use Wi-Fi calling or a calling app

Last verified: 1 November 2026. Sources: Apple, travel eSIM, T-Mobile IMEI check, AT&T Prepaid BYOD.

Is it unlocked?

On an iPhone, open Settings > General > About. Find "Carrier Lock". If it says "No SIM restrictions", the phone is unlocked (Apple).

On Samsung, Motorola and other Android phones, the menu name differs by brand. We could not re-check the exact paths, so look on the maker's support site for your model, or ask your home carrier. Only your carrier can unlock a locked phone. Do not use unofficial unlock services. If the phone is locked, ask early. Carriers can need days, and they may ask you to finish paying for the phone.

eSIM and dual SIM

Apple says travel eSIMs need an iPhone XS, XS Max, XR or later (Apple). A phone with a SIM tray and an eSIM can use both at once. That lets you keep your home number on the physical SIM and use the visitor eSIM for data.

AT&T's pass needs an unlocked, 5G-capable, dual-SIM phone with an open eSIM slot (AT&T).

Bands and VoLTE

Look up your exact model number, not the marketing name. Dial *#06# to see the IMEI. Run the IMEI through T-Mobile's checker. T-Mobile says it cannot guarantee that devices from other carriers will work and that the device must support T-Mobile's frequencies. AT&T keeps a list of approved devices. In its list, the Galaxy S20 model G981U is marked "will work" and model G981N is marked "will NOT work" (AT&T device list, PDF last updated November 2022). The same marketing name can hide a different model. For examples from Apple's spec pages, see why your phone's bands matter.

Step 2: Choose your path

PathWhat you needTypical costMain advantageMain riskBest for
A: travel eSIM, bought before you flyUnlocked eSIM phone, home Wi-Fi, any cardFrom $3.99 (1 GB) to about $70 for a month of "unlimited" (prices)Data on landing. No US ZIP code or addressMostly data only. Daily capsShort trips, light use
B: carrier visitor eSIM, bought on arrivalUnlocked eSIM phone, Wi-Fi on arrival, a card the app acceptsT-Mobile $25 / 7 days + tax. AT&T $3.99 to $59.99A real US network plan. Hotspot. Some include callsSign-up after you land. Card and ZIP problems1–4 weeks, heavier use
C: store or retailer, SIM or eSIMUnlocked phone and a payment method the store acceptsT-Mobile SIM kit about $10 plus a first month of $50Staff can helpQueue, opening hours, a 30-day planLonger stays, or a phone without eSIM

Last verified: 1 November 2026. Costs are summaries. The full table is in the cost guide.

Rules of thumb:

  • Your phone has no eSIM: use Path C with a physical SIM. The phone must still be unlocked.
  • Your card has failed at US merchants before: use Path A, or pay in a store.
  • You need US SMS codes: use a plan that gives you a US number. The T-Mobile and AT&T pass pages do not say whether a number is issued, so ask first.
  • You land at night: do Path A. Or buy the visitor pass the next morning on hotel Wi-Fi. The T-Mobile pass starts at purchase.

Path A, before you fly: a travel eSIM

  1. At home, on Wi-Fi, buy the plan in the provider's app or website.
  2. Install the eSIM. On an iPhone, follow Apple's steps for adding a travel eSIM (Apple). Label the new line "USA" so you do not mix it up with your home line.
  3. Check on the provider's page when the validity period starts. Some start at install, some at first connection. If you cannot tell, install the eSIM but wait to buy until the day before you fly.
  4. On arrival, set the USA line for mobile data (see Phone settings). Keep your home line on for calls and SMS, with Data Roaming off.
  5. Apple's flow for a travel eSIM offers Low Data Mode during setup. It is a cheap way to make a small plan last.

Catch: most travel eSIMs are data only. If you need a US number, read the plan page for the words "phone number" before you pay.

Buy a travel eSIM before you fly: Check current price: Airalo · Saily

Path B, on arrival: a carrier visitor eSIM

T-Mobile U.S. Pass

Read this part before you fly.

  • You must complete the purchase inside the United States (T-Mobile). You need Wi-Fi at the airport or your hotel to install it.
  • Your phone must be SIM-unlocked.
  • The plan starts at purchase. The day you activate counts as Day 1. Buy it on the day you need it.
  • Payment: "domestic and international credit and debit cards from select countries". T-Mobile's page does not list the countries.
  • No ID, paperwork or store visit is required, according to the same page.

What the app asks for (T-Mobile support): an email address, a PIN of 6 to 15 digits, and a US ZIP code. It may ask for your location. At payment you enter the card number, CVV and a billing ZIP. Then you download the eSIM to the phone.

For the ZIP code, use the real address where you are staying. Enter your card's real billing details. If the form rejects your non-US billing address, do not invent one. Try another card, buy in a store, or use Path A. You can also call T-Mobile on 877-778-2106.

To use data in Canada or Mexico, buy and activate in the US first. Then add the free Canada and Mexico add-on by the SMS link or by "Add Services" in your account, and turn Data Roaming on.

Visitor pass bought on arrival: Check current price: T-Mobile U.S. Pass

eSIM by AT&T

AT&T's steps, as we read them (AT&T, AT&T support):

  1. Use the Connect on Demand by AT&T app to check that your phone is eligible.
  2. Once you are in the US and your phone connects to a wireless network, buy an eSIM plan in the app. AT&T's terms say you may look at plans before you arrive, but a purchase needs you to be physically in the US.
  3. Download the eSIM.
  4. Set the Connect on Demand eSIM as your data line. For a talk plan, set it as the default voice line.

Requirements: an unlocked, 5G-capable, dual-SIM phone with an open eSIM slot.

The pass is offered only to people who do not live in the US, decided by your phone number (AT&T terms). That means your phone should still carry your non-US number when you buy. Refunds are given only if the eSIM fails to download or activate. Plans are not transferable. Government taxes are extra. The hotspot allowance is 5 GB, then a maximum of 128 kbps. You can top up in the app.

What we could not find: how the app checks your phone number while your home SIM is abroad, and which payment methods it accepts. AT&T's terms say only that a one-time payment is required and that you need a wireless connection to buy. Run the eligibility check in the app before you fly, and ask AT&T about payment.

Path C, in a store or retailer: a prepaid SIM or eSIM

T-Mobile. The SIM starter kit is sold at about $10 (the page text is garbled; we read "$1000" as $10.00). There is no activation fee when you activate online. An in-store activation can cost $10 (T-Mobile). The kit page we read shows only ship dates. We found no official page on shipping kits to addresses outside the US, so buying in a store is safer. For an eSIM, T-Mobile's web activation page says your new number appears on the Welcome screen (T-Mobile).

AT&T Prepaid. AT&T offers a free SIM when you switch with your own phone and says there is no activation fee online. Activate at att.com/activateprepaid or call 877-426-0525 (AT&T; the activation help article was last updated in August 2024). The phone must be unlocked.

Verizon Prepaid. Verizon says it will ship a new SIM at no cost (Verizon). Shipping needs a US address.

Mint. Mint activates an eSIM in its app. You enter an 11-digit eSIM code, and Mint assigns a new number based on a ZIP code (Mint).

Ask for a prepaid plan in a shop. We could not confirm which stores sell prepaid SIMs to visitors, or what ID they ask for. T-Mobile community threads on this topic could not be read in full, so treat any forum claim as unconfirmed.

Foreigner pitfalls: ZIP codes, cards, addresses and ID

Most problems for visitors are not about the phone. They are about forms made for US residents. Here is the map.

PitfallWhere it shows upWhat to doStatus
US ZIP code fieldT-Mobile eSIM app asks for a US ZIP and a billing ZIPUse the real address of your stay. Enter your card's real billing details. If rejected, use another card, a store or Path ARead on T-Mobile support. Not tested with a non-US card
Foreign card acceptanceU.S. Pass: "international … cards from select countries"Try a second card. Pay in a store. Ask T-MobileThe country list is not on the page we read
"Reside in the U.S." wordingTerms for T-Mobile's tourist and monthly plans include "you must reside in the U.S."Ask T-Mobile on 877-778-2106 how this applies to a visitorFound in the support page terms. The product page says the pass is for international travelers
Physical SIM shippingOnline kits ship inside the USBuy in a store, or use an eSIMNo official page on non-US shipping found
AT&T eligibilityThe pass is offered only to people who do not live in the US, decided by phone number. The app also asks you to verify your numberKeep your non-US number in the phone. Run the eligibility check before you flyTerms read. The verification method is not documented
Buy only inside the UST-Mobile U.S. Pass and eSIM by AT&TDo not buy before flying. You can look at AT&T plans earlier. Plan for airport Wi-FiRead on T-Mobile and AT&T terms
Activation clockU.S. Pass starts at purchaseBuy on the day you need itSame page
Auto-renew confusionFAQ: "no autorenewal". Support-page terms: services "automatically renew"Check the plan screen after purchase. Set a reminderBoth read. Pages conflict
RefundsFAQ: "limited". Support-page terms: "Non-refundable"Do not buy earlyBoth read. Pages conflict
Bank blocks a US merchantA first purchase from a US telecom firm can be flaggedTell your bank before you travelGeneral advice, not from a provider page
Promo codesVisible's offers use codes with end datesDo not plan around a codeSeen on Visible plans
Free trialsVisible's 15-day free trialNeeds you to be in the USSeen on Visible's trial page

Last verified: 1 November 2026.

Phone settings, step by step

Do these after the eSIM is installed or the SIM is in.

iPhone

  1. Open Settings > Cellular. Label each line (for example "Home" and "USA").
  2. Under Cellular Data, select the USA line (Apple).
  3. Tap the USA line > Cellular Data Options > Data Roaming. Turn it on for this line (Apple).
  4. Tap your home line. Turn Data Roaming off, so your home carrier does not bill roaming data.
  5. If your plan is small, open Cellular Data Options and set Data Mode to Low Data Mode (Apple iPhone guide).

Android and Pixel

  1. Open Settings > Network & internet > SIMs.
  2. Choose the USA SIM for Mobile data.
  3. Turn on Roaming for that SIM (Google, Pixel).
  4. Set a warning: Network & internet > SIMs > Data warning & limit.
  5. To save data, turn on Data Saver: Settings > Network & internet > Data Saver (Google).

On Samsung phones the roaming switch is under Settings > Connections > Mobile networks > Data Roaming Access (Samsung). Other brands use other names.

APN

Phones usually set the APN by themselves. Change it only if you have no data after the other steps.

NetworkValuesStatus
T-MobileAPN: fast.t-mobile.com. MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc. Leave the other fields as the phone proposesRead on T-Mobile's APN page. T-Mobile says it cannot guarantee these settings make an unsupported phone work
Mint, AT&T, Verizon, Visible, Tello, US MobileUse only the values on each provider's own pageWe did not open these pages. Mint's activation page links to a separate guide
Travel eSIMsSet by the eSIM profileSee the provider's help page

Last verified: 1 November 2026.

To reset an iPhone's network settings, use Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings (Apple). It removes saved Wi-Fi networks and VPN settings. Apple says it may also turn off cellular data roaming, so check that switch again.

Wi-Fi calling, VoLTE and keeping your home number

With two lines, keep the home line for SMS and bank codes. Turn Data Roaming off on it. Your home operator may still charge for incoming calls or texts abroad, so check its price list. We have not checked any operator.

Use iMessage, FaceTime or a calling app over the USA data line. Visible says all its plans include unlimited calls and texts over Wi-Fi without using data (Visible).

VoLTE is how modern US networks carry voice calls. If data works but calls fail, T-Mobile asks you to check VoLTE support and turn VoLTE on (T-Mobile BYOD guide).

Troubleshooting "no data" and "SOS only"

Work down the list. The first rows are the most common.

SymptomLikely causeFix (in order)
"SOS only" or "No service"Network not attached yet, wrong date and time, roaming offRestart the phone. Check you have at least two bars. Make sure Airplane Mode is off. Set Date & Time to automatic (Settings > General > Date & Time). Turn on Data Roaming for the line
Bars but no dataWrong line chosen for data, or roaming offSettings > Cellular > Cellular Data: pick the USA line. Turn Data Roaming on for it. Turn Wi-Fi off to test
eSIM installed but no planThe line is switched off, or the plan has not startedCheck the line is on under Settings > Cellular. Check the provider app for plan status
Cannot download the eSIMNo Wi-FiConnect to Wi-Fi and try again
Works in the US, not in Canada or MexicoU.S. Pass add-on not activated, or roaming offActivate the free add-on. Turn Data Roaming on
Data works, calls do notVoLTE or Wi-Fi calling offTurn on VoLTE if the phone shows it. Restart. Use Wi-Fi calling or a calling app
Still no dataAPNReset network settings, then set the APN from the table above
Bought the pass too earlyThe plan starts at purchaseCall 877-778-2106. T-Mobile says refunds are limited
Home carrier charges roamingHome line is using dataTurn Data Roaming off on the home line. Choose the USA line for Cellular Data
Payment declinedCard country not accepted, address mismatch, bank blockTry another card. Pay in a store. Tell your bank

Sources: T-Mobile troubleshooting (restart, bars, Airplane Mode, roaming, Wi-Fi), Apple (Data Roaming per line). Last verified: 1 November 2026.

Your first hour on the ground

This order avoids most mistakes.

  1. Turn Airplane Mode off and connect to airport Wi-Fi. Path B needs Wi-Fi to buy and install. Path A needs it for nothing else, but you will want it for the next steps.
  2. Pick your data line. If you installed a travel eSIM before the flight, set it for Cellular Data now (see the phone settings above). If you are buying a visitor pass, do it now, because the pass starts at purchase.
  3. Turn Data Roaming on for the USA line only. Turn it off for the home line.
  4. Run the 60-second test. Open a map. Load one web page. If both work, you are done.
  5. Set a data warning. On Android, use Data warning & limit. On iPhone, use Low Data Mode if the plan is small.
  6. Download an offline map of your city on Wi-Fi. It is a fallback if the signal drops.
  7. Message home. A short text to family confirms that SMS and data both work.

Mistakes with two lines on one phone

Dual SIM is useful, and it creates its own errors.

  • The home line is still the data line. This is the most expensive mistake. Check Settings > Cellular > Cellular Data and pick the USA line.
  • Data Roaming is on for the home line. Turn it off on that line only.
  • The USA line is installed, but it is switched off. Check the line is on under Settings > Cellular.
  • You deleted the eSIM too early. Before you remove an eSIM, check the provider's help page. Some eSIMs cannot be installed again.
  • You switched off the home line completely. Then you cannot receive bank codes by SMS. Keep it on, with data off.

Before you contact support

Support goes faster when you have the facts ready. Collect these:

  • The phone's exact model number (it is on the About screen) and the system version.
  • The order email or receipt, and the time you bought the plan.
  • A screenshot of the error message, and of the line and roaming settings.
  • The result of the 60-second test, and whether Wi-Fi was on.

Share your IMEI only with the provider's own app, chat or phone line. Do not post it, your eSIM code or your QR code in forums or photos. For the T-Mobile U.S. Pass, the page lists 877-778-2106. For AT&T Prepaid activation, AT&T lists 877-426-0525.

Checklists

Before you fly: phone unlocked. Model and bands checked. Home carrier's roaming price known. Travel eSIM installed (Path A). Bank told. Offline map downloaded on Wi-Fi.

On landing: connect to airport Wi-Fi. Buy the visitor pass (Path B) when you are ready to use it. Set the USA line for mobile data. Turn Data Roaming on for that line. Turn it off for the home line. Do a 60-second test: open a map and load a web page. Set a data warning on Android (Network & internet > SIMs > Data warning & limit), or Low Data Mode on iPhone.

Before you leave: delete the travel eSIM, or turn the line off. Turn the home line back on. Check the plan will not renew.

FAQ

Can foreigners buy a US SIM card or eSIM? Yes, in most cases. T-Mobile says the U.S. Pass needs no ID or paperwork. Card and ZIP problems apply. See the pitfalls table.

Do I need a US address or ZIP code? T-Mobile's app asks for a US ZIP code. Use the real address of your stay. Do not invent one.

Can I buy a US eSIM before I fly? Travel eSIMs, yes. T-Mobile's U.S. Pass and eSIM by AT&T, no: both need you to be in the US when you buy. You can look at AT&T's plans before you travel.

Will my European phone work in the US? It depends on unlock status, eSIM support and the exact model's bands. Use Step 1 and the band examples.

How do I check whether my phone is unlocked? On iPhone, Settings > General > About > Carrier Lock. On Android, ask your carrier or the maker's support page.

Do I need to type APN settings? Usually not. Only if data fails after the other steps. T-Mobile's values are in the APN table.

Why do I see "SOS only" or no data? Use the troubleshooting table, from the top.

Can I keep my home number active while using a US eSIM? Yes, with a dual-SIM phone. Set data to the USA line and turn Data Roaming off on the home line.

Last-tested date and change log

Last read: 1 November 2026. Not tested by us: every purchase flow, app screen, card, and store visit.

Change log

  • 2026-11-01: First version.

Sources

All pages read 2026-11-01 unless noted.