The Ontario Line is a 15.6-kilometre stand-alone rapid transit line that will connect the Ontario Science Centre to Exhibition/Ontario Place. Over half of the route is planned to run underground through new tunnels, with the remainder running along elevated and at-grade rail corridor sections of track. Fifteen stations are proposed, with numerous connections to the broader transit network, including GO Transit rail services, the Toronto Transit Commission's subway Lines 1 and 2, the future Line 5 (Eglinton Crosstown LRT), as well as numerous bus and streetcar routes.
The Ontario Line is one of four priority transit projects announced by the Province in 2019 for the Greater Toronto and Hamilton Area. Planning is underway for all four subway projects and procurements for the subway program are being staged to ensure each project is delivered successfully.