Before you start

An unlocked handset, or an eSIM-capable one
A US address for postpaid, but not for prepaid
A payment method — prepaid accepts foreign cards, postpaid usually does not

Step-by-step

1
Activate an eSIM before flying, or buy prepaid on arrival
A US eSIM activates before you land so you have a working number immediately for rides, deliveries and bank verification codes. No identity registration is required at any point.
OnlineWho: YouDay 1
2
Check your handset is unlocked and band-compatible
Phones bought on contract abroad are frequently locked, and US band combinations trip up some regional models. With 3G shut down there is no fallback network to land on.
OnlineWho: You
3
Start prepaid rather than fighting a credit check
Postpaid runs a credit check. With no US file you will be declined or asked for a deposit. Prepaid has no check and is usually cheaper for the same data allowance.
OnlineWho: You
4
Turn on Wireless Emergency Alerts and a weather radio app
Flash flood warnings, severe thunderstorm warnings and tornado warnings arrive on the handset through the federal alert system. In Flash Flood Alley these are the difference between rerouting and driving into water. Check the alert settings are enabled — some are on by default and some are not.
Mobile appWho: YouWeek 1
5
Keep a power bank and know your carrier's outage behaviour
Texas's grid is largely disconnected from the rest of the country and cannot import much power in a crisis, which is what made the February 2021 freeze so severe. Mobile sites have battery backup measured in hours, not days. A charged power bank and a car charger are standard local preparedness.
In personWho: You
6
Port rather than cancel if you switch later
Number portability is a legal right and works between carriers and MVNOs. Request the port from the new carrier — never cancel the old service first, or you lose the number.
OnlineWho: You

Documents you’ll need

Passport for postpaid; nothing at all for prepaid
US address for postpaid
A payment card — prepaid usually accepts foreign cards, postpaid rarely does

Things most newcomers don’t know

The emergency alerts are the local safety system, and they are opt-out.

In a flash flood region the National Weather Service's warnings reach you through the phone. Some alert categories can be silenced in settings and people do silence them after one loud test. Leave the flood and tornado categories on — the region's flood deaths are overwhelmingly people who did not know a road ahead had gone under.

Source: FCC — Wireless Emergency Alerts

Texas's grid isolation is a phone-charging problem too.

ERCOT covers most of Texas and has only limited connections to the rest of the North American grid, so a Texas shortage cannot be substantially covered by imports. During the February 2021 freeze that meant multi-day outages, and mobile sites run on batteries measured in hours. A power bank in the drawer is the cheapest insurance available here.

Source: community-reported

The credit check is the barrier, not the documentation.

Carriers check credit before offering postpaid, and a newcomer with no file gets declined or charged a deposit. Prepaid sidesteps it entirely and usually costs less for the same data.

Source: community-reported

The US has no SIM registration at all.

Most countries in this app require passport registration to activate a SIM. The US requires nothing whatsoever for prepaid — you can buy one in a supermarket and be online in minutes.

Source: FCC — consumer guides

Common mistakes to avoid

Silencing weather alerts after one loud test, in a flash flood region.
Applying for postpaid with no credit file and facing a large deposit.
Bringing a carrier-locked handset from abroad and discovering it on arrival.
Assuming fibre is available at a new-build address because the estate advertises it.
Cancelling the old carrier before requesting the port, and losing the number.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.

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