There is no subway service on Line 1 between St George and Downview stations this weekend due to signal upgrades, the Toronto Transit Commission says.
All trains on Line 1 will turn back southbound at St George station.
Shuttle buses will run between Downsview and Lawrence West stations during the shutdown because several construction projects on the street are affecting traffic, according to the TTC.
There is no shuttle bus service from St George station.
"Customers are encouraged to use existing east and west bus and streetcar routes to the Yonge portion of Line 1 or north and south bus routes to Line 2. Additional service is being added to these routes during the subway closure," the TTC says.
The TTC encourages customers on Line 2, who want to travel northbound, to transfer at Yonge-Bloor station.
Dupont and Glencairn stations will be closed. All other stations, between St George and Downsview stations, will be open for fare sales and customers using buses or streetcars.
Wheel-Trans buses will run between Downsview and St George stations upon request. Customers can request the service by asking TTC staff.
If heading to Yorkdale Mall, the TTC encourages customers to take alternate routes during the subway shutdown.