Layover in Toronto

There's a train that goes downtown (25 minutes each way) from the airport, but I don't know if it's worthwhile to you for such a short trip. Pearson can be very busy - there's no way of knowing how much time to allow because it just "depends". It's a really nice airport, I don't mind hanging out there for hours if need be.

https://www.upexpress.com

If you are not in biz class or better with lounge access, perhaps buy a day pass; take a shower, eat, drink and unwind

I suggest you visit areas nearby airport only. 6 hours is very short time period to move out of airport, explore a place and then head back to the airport. I am sure you don't want to miss your flight.

Wherever you are in the world, if you are leaving the airport, it could take say an hour to get through immigration and you will presumably have to be back at the airport 2-3 hours before your onward flight, depending on if you are booked through or on separate tickets, which doesn't leave much time for exploring.

I had a similar layover two weeks ago and decided to take the express train downtown for a few hours, dropped my bag at the Samsonite store. A very easy journey and the market is not far from Union Station. It made for an enjoyable morning and much better than sitting in the airport. It did not take long for me to go through security for a flight to the US, I went through near noon on a Wednesday. I would do it again.

"It did not take long to go through security for a flight to the US."

That was then. Starting this week, there is "enhanced security" for all flights to the USA from airports in .Canada. Expect longer lines, shorter tempers and general disgruntledness all round.

Agree with other posters. With that short time, stay at the airport.

While it is a beautiful airport (compared to some in the US), we've found it is not the easiest airport from which to depart, especially if you have a smaller regional jet for your final leg home. We've experienced long security lines (even though we are Global Entry and therefore pre-check). The issue we faced was that the Global Entry was not entirely set up (at that time) for the regional jet concourse, but that might have changed since it was 2016 when we last connected thru Toronto. The regional jet concourse was also extremely crowded....packed (in its truest sense) with departing passengers, along with some delays in takeoff for some planes (which likely added to the crowded conditions). Communication from the on-ground airline personnel was not great in the way of announcement updates (likely they just did not know status of flights), but they were very kind with one-on-one inquiries. Elderly friends with whom we had traveled were returning thru Toronto the day following us, and their response was "never again."

Granted, a lot can change in a year, and likely everything is smooth as silk now; but with only 6 hours, there is no way I would risk leaving the airport and starting all over again with security lines, etc.

Have a great trip, and safe travels.