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
A plan for keeping the phone out of direct sun in summer

Step-by-step

1
Activate a US eSIM before you fly, or buy prepaid on landing
An eSIM bought before departure means you land with a working US number, which matters because banks, MVD and rental applications all send SMS codes. No identity registration is required at any point in the US.
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2
Check your handset is unlocked and band-compatible
Handsets bought on contract abroad are frequently carrier-locked, and some regional models miss US band combinations. With 3G shut down there is no fallback network. Run your exact model through the carrier's compatibility tool.
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3
Start prepaid rather than fighting a credit check
Postpaid runs a credit check and a newcomer with no file is declined or asked for a deposit of several hundred dollars. Prepaid has no check, no contract and is usually cheaper for the same data on the same network.
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4
Never leave the phone on a dashboard or mount it in direct sun
Handsets thermally throttle and then shut down entirely in Phoenix summer conditions, and a phone left in a parked car can be permanently damaged. A vent-mounted holder in the airflow, a light-coloured cover and a habit of putting the phone in the centre console when parking are what locals do. Losing navigation at 45°C is a safety issue, not an inconvenience.
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5
Download offline maps before any desert or mountain trip
Coverage in the metro is uniformly good and disappears quickly in the Tonto National Forest, the Superstitions and on the drive up to Flagstaff. Newer handsets support satellite SOS, which is genuinely useful here. Download the offline map, tell someone your route, and carry more water than the hike suggests.
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6
Get home internet by exact address
Cox is the dominant cable provider across most of the Valley, with CenturyLink and Google Fiber's newer Mesa and Chandler builds competing in places. Availability is address-specific and the difference in upload speed between fibre and cable is large. Check before you sign a lease if you work from home.
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Documents you’ll need

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

Things most newcomers don’t know

Your phone will shut itself down in the summer, usually while navigating.

Handsets thermally throttle above roughly 35°C ambient and shut down entirely well below Phoenix's summer peak, and a windscreen mount in direct sun reaches that within minutes. Locals mount phones in the air vent rather than on the glass, keep them out of parked cars, and treat a sudden thermal shutdown as normal rather than a fault. Losing navigation on an unfamiliar freeway at 45°C is the actual risk.

Source: community-reported

Coverage stops abruptly once you leave the Valley.

Metro coverage is excellent and the desert and mountains an hour out are close to empty of signal — the Superstitions, much of the Tonto National Forest and stretches of the drive to Flagstaff. Phoenix's culture pulls newcomers into that terrain quickly, in a climate where a breakdown or a twisted ankle is a heat emergency. Offline maps, a full tank, extra water and satellite SOS are the standard local precautions.

Source: community-reported

The US has no SIM registration of any kind.

Most countries in this app require passport registration to activate a SIM and several require biometrics. The US requires nothing at all for prepaid — you can buy one with cash and never give a name. Arriving from Mexico, India or the Gulf, the total absence of paperwork reads like an oversight. It is deliberate, and it is the fastest thing you will do all month.

Source: community-reported

The credit check is the barrier to postpaid, not the paperwork.

Carriers screen credit before offering a postpaid plan and a newcomer with no file is declined or charged a deposit of a few hundred dollars. Nobody at the counter explains that prepaid avoids the check entirely, runs on the same towers, costs less, and can convert to postpaid later once you have history.

Source: community-reported

Common mistakes to avoid

Leaving a phone on a dashboard or windscreen mount in summer and cooking it.
Driving into the desert or up to Flagstaff without offline maps and extra water.
Bringing a carrier-locked handset and discovering it after landing.
Applying for postpaid with no credit file and facing a large deposit.
Relying on a foreign number for bank and MVD SMS verification.

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