Auto insurance is very specific concerning the areas of policy coverage. If you are traveling to a different country, it is best to speak to your agent or review your policy to determine where, geographically, you are covered in the event of a loss.
For example, for a trip from the U.S. to Mexico, additional or supplemental insurance is usually required, and some carriers can add a special endorsement for additional coverage. For a trip to Canada, you may not need additional insurance, depending on the length of your stay.
Most people do not ship their vehicles when traveling overseas, opting instead to rent a car at their destination, in which case you would obtain the appropriate international and overseas coverage for the country you are visiting when you rent the vehicle.