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.
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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 network to land on.
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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.
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4
Assume degraded service during the big conventions
When a show of CES's size is in town, the cell sites around the convention centre and the Strip carry many times their normal load. Carriers deploy temporary capacity but it is not enough. If your work depends on connectivity in those weeks, have wifi calling configured and a backup.
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5
Check desert coverage if you leave the valley
Coverage across the valley is uniformly good. Twenty minutes into the desert — Valley of Fire, the Spring Mountains, the roads towards Death Valley — it stops, and the gaps are long. Download offline maps before you go rather than after you have lost signal.
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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.
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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

Convention weeks are a predictable outage, and you can plan around them.

The valley's network load is not uniform across the year. During the largest trade shows the sites serving the Strip and the convention corridor saturate, and calls and data around them get unreliable. Locals know which weeks these are from the convention calendar. Configure wifi calling before you need it.

Source: community-reported

MVNOs get deprioritised exactly when the city is busiest.

MVNOs lease capacity and their traffic drops behind the host carrier's during congestion. In a city whose entire economy is periodic mass gatherings, that difference is more noticeable here than in most places. For ordinary suburban life an MVNO is fine; if you work events, the main carriers behave better.

Source: community-reported

The desert coverage gap is a safety matter, not an inconvenience.

The Mojave starts at the edge of the valley and the roads through it have long stretches with no signal at all, in a climate where a breakdown in July is dangerous within hours. Carry water, tell someone your route, and download offline maps. A handset with satellite SOS is genuinely useful here.

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