How to call Ottawa in Canada from United States:
1 - Exit code when making an international call from United States
1 + (613 or 343 or 819 or 873) + Local Number - International dialing code format
Note: Canada and United States are both members of NANP (North American Numbering Plan) so when calling between these countries, 1 is used in place of the country exit code.
World time zone information: