What area codes when I use my 'bolt on' in USA

[Chameau]

Sorry this is probably a very basic question. I have just bought an international bolt on so I can use my iphone when I go to the US. Do people calling me still have to use the UK area code? When I'm calling a US phone, do I still need to use the US area code? Many thanks, Martin

[Cleoriff · Accepted solution]

@Chameau 

The international Bolt on wont be any good to you whilst in the US I'm afraid. It's for calls and texts FROM the UK to countries abroad.

Edited to add you need O2 TRAVEL or O2 TRAVEL EXCLUSIVE whilst you are in the US. All info here

Guide: Roaming MegaGuideotherwise you will be paying international rates.

Data is also capped to 25GB.