Canada is the world's second-largest country by area, and mobile coverage is concentrated mostly along the southern border, where most of the population lives. Here's which eSIM to get for Toronto, Vancouver, Montreal and national park trips.
For a week in Toronto, Vancouver or Montreal with navigation and social media, 5–8 GB is usually enough. For a road trip with national park visits and constant navigation, get 10–15 GB or more.
Coverage is fast and reliable almost everywhere in Toronto, Vancouver and Montreal. In national parks — Banff, Jasper, the Rockies — signal can drop for long stretches away from towns, simply due to how sparsely populated the area is. It's worth downloading offline maps for those routes.
You can install the profile at home ahead of time, then turn on data roaming after you land in Canada, so the plan doesn't start being used early.