As of March 2023 there are no requirements of testing prior to arrival in Canada, no requirements for vaccination, prior to arrival, and no quarantine or test requirements after arrival. As in any situation however the government can theoretically request that a test be performed at the arrival airport.
Current Federal travel guidance can be found here: https://travel.gc.ca/travel-covid
There are no general mask requirements anywhere in the country, though large cities recommend their voluntary use in enclosed areas. Most provinces however require a mask in health care settings, though as far as we have observed those masks are generally provided upon entry. Individual businesses, organisations, facilities or public events may require a mask for access. It is wise to keep a mask in your kit for those circumstances.
Any of this can change at any moment and this page may not be up-to-date.
Per-province/territory guidance and rules:
Prince Edward Island
Newfoundland & Labrador