I'm thinking of spending time visiting Toronto, Ottawa, Montreal and Quebec City this summer. Can I do without a rental car in these places and rely on public transportation? I plan to either fly or take the train between these cities. I could rent a car for a day when needed. Thanks.
Flying wouldn't really make sense if you are doing the logical east-west (or vice versa) progression. There is good train service, as mentioned. Plus the cost of gas... 'nuff said.
As long as you are staying in, and visiting the sites, that are centrally located in each city, then public transportation and the odd Uber ride should get you where you need to go.
Both Montreal and Toronto have a subway system that you can access from their train stations. If you fly into Toronto you can take the Union-Pearson Express from Pearson right downtown to Union Station (the train station). The UP Express makes a couple of stops along the way where you can get on the subway if you don’t want to go all the way downtown. It takes about 1/2 hr from airport to train station.
In Ottawa you can take the LRT from the train station to downtown, it’s about 4 or 5 stops, depending on where you want to get off.
If you buy a Prestocard ($6) and load it you can use it in both Toronto & Ottawa. There is also Presto contactless payment. See prestocard.ca for information.
Hoping someone else chimes in for Quebec City, we were there a long time ago and drove from Ottawa.
Thanks to its hilly geography and old city walls, the centre of Quebec City is pretty compact and easy to walk. Parking in the old parts of the city can be a challenge. A car rented for a day would help you explore the countryside and banks of the St. Lawrence River. If you arrive by air, access to and from the airport by public transport is a real problem. The main train station is in the downtown core.