Yes, absolutely, but as the watch is effectively a smartphone, you will need to take care of roaming charges unless they are included by the plan you are on. Many US providers have Canada and Mexico as North America since they are part of the same continent and are not considered roaming.
If this is not the case with your provider, you can purchase a local SIM card at your destination. As long as the local SIM plan includes sufficient minutes and data, it ought to work. Your Angel Watch™ app account and watch region must always be the same, even if you travel (e.g. if you ordered a North American watch, please make sure you created a North America Angel Watch™ app account and don't change this-even if you put in a foreign SIM card).
It is also recommended to save your US numbers in the following format +15551231234 to ensure the country code of the number is routed correctly when overseas.