How do you dial a US cell phone from a UK cell phone?

The telephone country code for the United States is +1, followed by a three-digit area code and a 7-digit subscriber number. US mobile numbers are indistinguishable from landline numbers, using the same geographic area codes, and calls to US mobiles are charged at identical rates to calls to U.S. landline numbers. On your UK mobile, just enter the number in international format, beginning with the plus symbol. If your mobile does not allow you to enter the plus symbol in a telephone number, substitute the UK's international access prefix 00 for the plus symbol.