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, which is useful at Hartsfield-Jackson — the busiest airport in the world and not a place to be sorting out connectivity. No identity registration is required at any point.
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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.
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.
OnlineWho: You
4
Consider an MVNO on the same towers
Mint Mobile, Visible, US Mobile and Google Fi resell capacity on AT&T, T-Mobile and Verizon. Same coverage for materially less.
Mobile appWho: You
5
Check coverage along the commute, not just at home
The metro sprawls sixty miles across and many people drive forty minutes each way. Coverage varies along the outer interstate corridors and in the north Georgia foothills. Check a carrier map against your actual route.
OnlineWho: 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.
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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 US has no SIM registration at all.

Most countries in this app require passport registration to activate a SIM and several require biometrics. The US requires nothing for prepaid.

Source: community-reported

Hartsfield-Jackson is the world's busiest airport, and it behaves like it.

Having a working US number before you land is more valuable here than in most cities — rideshare pickup at Atlanta is a genuine navigational challenge across multiple decks and terminals, and it is app-mediated. Sort connectivity before arrival.

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 and usually costs less.

Source: community-reported

MVNOs use the same towers for meaningfully less.

Mint, Visible, US Mobile and Google Fi lease capacity from the big three. Coverage is identical; you give up priority during congestion and retail support.

Source: community-reported