As long as you have a data connection. I suggest using wifi for the transaction, since roaming in the US would be expensive. You should also turn off Send as SMS in iMessage to make sure it doesn't try to send as an SMS if the iMessage fails.
This site contains user submitted content, comments and opinions and is for informational purposes only.
Apple disclaims any and all liability for the acts, omissions and conduct of any third parties in connection with or related to your use of the site.