How to dial a phone number in Monterrey Mexico?
From outside Mexico, a caller would dial their international call prefix (typically 00 in Europe and 011 in North America), followed by 52 (the country code for
Mexico), then 81 the 2-3 digit area code of the place you're calling (Monterrey) minus the trunk code '0', and finally the local number minus the trunk code '0'. All local telephone numbers dialled within Mexico must use the leading '0' and the area phone code, even when calling locally.
