How to call Guam from the USA or from Canada:

Calling Guam from the United States explained:

• 1 - Country Code for Guam
• 671 - area code within the NANP
• local phone number - 7 digits
• US to Guam international dialing format: 1 671 ??? ????
• this US territory is part of the North American Numbering Plan - NANP (calling it works like a US state to state call)

Phone Books:

• The Guam Phone Book