Hello all. I will be traveling to an international destination in June from Orlando FL. I have a stop in YUL with 3-hour layover. Would that be long enough? I have never gone through Canada before and don't know what to expect. And can someone please explain the process. Do I have to pick up my bags? Do I go through customs? I am going with Air Canada. Both flights. I have a US passport. This is my first time traveling overseas and I'm a little nervous

Air Canada should check your bag through to the destination. You should be able to print your two boarding passes at home 24 hours before departure. Technically you are not entering Canada, merely in transit. However, a new procedure for transit passengers has been added called Electronic Travel Authorization. It should be obtained on-line in advance and you need it for the transfer both going and coming.
https://www.canada.ca/en/immigration...anada/eta.html

Security for carry-on luggage has become stricter so it might take some time in Montreal. Three hours should be plenty, unless the first flight is seriously delayed. You didn't say where you are going. If part of the itinerary is on Air Canada Rouge, it would be wise to check the AC site to read about what services are (and are not) offered in this tourist-oriented sub-brand.

If you are returning to the US from Ireland you will be screened by US immigration and customs before the flight home. Otherwise you will be screened in Montreal. Be sure to stand in the appropriate line, which should be well marked. You may need to retrieve your luggage for US Customs there but I don't have personal experience. If so, the bag can be rechecked immediately after the customs process.

US passport holders do not require an eTA. You should verify this information yourself on the below link, or even the link provided by the above poster, which states the following

Travellers who are exempt from the eTA requirement. For example:

• U.S. citizens are exempt from the eTA requirement and must carry proper identification such as a valid U.S. passport.

This link allows you to enter your nationality and it checks whether you need an eTA

Find out if you need a visa

Thanks, Odin, an important distinction.

So I don't have to pick up my bags?