The towers will form a portion of Pinnacle One Yonge, a four-million-square-foot (372,000-square-metre) project that includes five new buildings and the renovation of an existing block.
The site is located at the end of Yonge Street, one of the Toronto's major north-south thoroughfares. Covering two city blocks, the plot fronts the harbour on Lake Ontario and is a short walk from the iconic CN Tower.
"The development, on Toronto's waterfront, rethinks the typical mix of residential, commercial and retail space found in Toronto," said a statement from Hariri Pontarini Architects.
"Designed to densify and enhance the urban streetscape, the project links to public transit, improves and widens sidewalks, and provides prioritised pedestrian and cyclist access with north-south and east-west mid-block connections."
The northern portion of the site, which is currently a car park, will host the three residential towers. Measuring 95, 80 and 65 storeys, they will incorporate a hotel, affordable housing, a community centre and retail spaces.
All will mainly be clad in glass, but each a slightly different aesthetic. The tallest is designed with visible diagonal bracings up its facades, while the middle tapers gently at the top. The smallest is more cuboid and will be first to be built.
To the south, two new office buildings reaching 35 and 22 storeys will join the current Toronto Star building completed in 1971, which will be refurbished and reclad.
The development will connect to Toronto's Union Station via an underground pedestrian walkway, and is intended to provide better access to the lake.
"The project will act as a gateway to the new waterfront community still under redevelopment, with a design that strives to set a new standard for dense, urban revitalisation," Hariri Pontarini Architects said.
Toronto is due to gain several towers that will dramatically alter its skyline. Earlier this month, Foster + Partners began work on a skyscraper set to become Canada's tallest, while proposals by Henning Larsen, BIG and Frank Gehry are all at various stages.
Founded by architects Siamak Hariri and David Pontarini in 1994, Hariri Pontarini Architects has also completed a Bahá'í temple in Chile.