Other events like Doors Open Toronto will take place across Ontario this year, with municipalities in the province set to offer free access to hundreds of off-limits buildings in the weeks and months to come. Doors Open Ontario includes 20 municipalities and regions in 2025, and with the busiest of the pack — Doors Open Toronto — now in the rear-view mirror, there will be many more opportunities to check out the province-wide celebration of heritage, buildings, and other rarely-accessible spaces. Toronto, Richmond Hill, Oshawa, Guelph, and Hamilton have already hosted their Doors Open events for 2025, but you can still road trip it to 14 more regions and municipalities, showing off their heritage and most notable landmarks. Here are the upcoming Doors Open Ontario dates for 2025:Doors Open Ontario began in 2002 and has grown exponentially in popularity during the past two-plus decades. The event has opened the doors to thousands of buildings in the province, welcoming over 9 million visitors and spurring more than $11 million in spending injected into local economies.