As an after-thought: there is one absolute "will not work" situation: that's if you have a phone from "3". Hutchison has not managed to find a roaming partner in the US, period.

Hutchison's phones, as provided with "3" accounts, will indeed work on GSM 1800, and some may well work on GSM 1900 as found in the US... but you'd have to get a US contract and swap the SIM card out. I don't know that it will fit, even; the USIM may not be compatible.

Final warning; GSM phones work in places like New York, San Francisco, and other large metro areas. Wander out into the wilderness, and no, you will find it's unlikely to get a signal.
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