Construction and opening Planning for the Science Centre started in 1961 during Toronto's expansion in the late
1950s and
1960s. In August 1964, Ontario Premier
John Robarts announced the creation of the Centennial Centre of Science and Technology as a
Centennial Project. Toronto
architect Raymond Moriyama was hired to design the site. Construction started in 1966 with plans to open the Centennial Centre of Science and Technology as part of the
Canadian Centennial celebrations in 1967. However, construction was not completed by 1967, and the Science Centre did not open to the public until two years later, on September 26, 1969. The official opening was held on the morning of September 27 and attended by a small group of guests, followed by an opening to a larger group of 30,000 guests in the early afternoon.
Operations from 1990 to 2022 International contract (1990) In 1990, the Ontario Science Centre announced a contract with
Oman to design a children's museum. At the time, the Centre had agreed to
boycott Israeli goods and services while under contract. The agreement was later amended to specify that all goods sold to Oman would be produced in North America. The Centre's director general, Mark Abbott, was subsequently dismissed for signing the original contract. In 1996, a redesigned entryway was opened, which contained an
Omnimax theatre. Beginning in 2001, a redesign funded by a mix of public and private capital was started. It was completed in 2007.
Renewal: Agents of Change (2001–2007) Beginning in 2001, the Science Centre launched a major renewal initiative known as
Agents of Change, aimed at modernizing facilities and programming. The project renewed approximately 85 percent of the Centre's public space and created seven new experience areas. Funding for the initiative totaled $47.5 million and included contributions from the
Government of Ontario, private-sector companies, and individual donors. The
Agents of Change transformation was completed in 2007, marked by the opening of the Weston Family Innovation Centre and the TELUSCAPE plaza.
COVID-19 outreach (2020) During the
COVID-19 pandemic, the Science Centre received $500,000 from the
Government of Canada to support efforts promoting COVID-19 vaccine uptake among children and their families.
Facility decay, replacement plans, and closure From 2023 until the Don Mills site's closure, a shuttle bus ran from the Science Centre's entrance to the main exhibit area on the museum's Level 6, due to structural decay in the pedestrian bridge that led to the exhibit area, located at the bottom of the Don River ravine. On April 18, 2023, Ontario Premier
Doug Ford announced the provincial government's plan to relocate the Science Centre to a new facility on the grounds of
Ontario Place on the Toronto waterfront. This announcement was met with widespread public backlash due to concerns about potential downsizing and exhibit losses. Both the Architectural Conservancy of Ontario and the Toronto Society of Architects condemned the relocation plans, while the grassroots group Save Ontario's Science Centre organized rallies and campaigns to reverse the government's decision.
Toronto City Council also sought to keep the Science Centre at its original location. In December 2023, the
Auditor General of Ontario concluded that the government's decision "was not fully informed and based on preliminary and incomplete costing information, and had proceeded without full consultation from key stakeholders or a clear plan for the existing site". On June 21, 2024, the
Ministry of Infrastructure announced the immediate and permanent closure of the Don Mills location, citing an engineering report revealing water damage affecting 2-6% of the building's roofs. The report estimated that repairs would cost at least $22 million and take two years to complete. Safety concerns about the roof material in question,
reinforced autoclaved aerated concrete (RAAC), had caused the temporary or permanent
closure of hundreds of buildings in the United Kingdom in 2023. The
Ford government expedited its plan to relocate the Science Centre to the waterfront, targeting a 2028 opening, with a temporary location slated for January 2026. The decision drew further criticism, including from Moriyama Teshima Architects, the firm founded by the Science Centre's original architect. The architects offered to do
pro bono design consulting services for the Government of Ontario to support immediate repairs to the roof, and called for other organizations to join the effort to facilitate repairs. Private donors, including
Geoffrey Hinton, offered up to $1 million to fund repairs for the existing facility, but the province did not respond to these offers.
Closure validity In May 2025, the
Canadian Architect magazine obtained the drafts of the structural report done by the Rimkus Consulting Group. Dated to the spring of 2024, the drafts recommended routine repairs of the roof with a strong emphasis on RAAC panel replacement, a straightforward project that had already been put into effect for the most critical panels. Although there was mention of "full closure" in the final report, restricted access would only be needed for a "minuscule portion" of the high-risk roof areas. The report drafts are considered alongside a 2024
Global News story that highlighted a frequent chain of communication between Rimkus and
Infrastructure Ontario prior to the report's official submission. It is implied that the "supplemental risk mitigation options" were only inserted in response to political pressure. The suggestion of restricted access and the potential consequences of preventing repairs appear to be the primary justifications for a full closure of the centre.
Temporary locations and original site uncertainty By October 31, 2024, most of the exhibits had been moved to storage facilities in northern Toronto and
Guelph, while the animals and plants had been transferred to the
Toronto Zoo and
The Village at Black Creek. Temporary pop-up exhibits have since opened at
Sherway Gardens and Toronto's
Harbourfront Centre. In December 2024, the Auditor General of Ontario questioned the financial prudence of the relocation. Contrary to the Ford government's business plan analysis, which projected $257 million in savings over 50 years, the AG found that relocation costs have already exceeded the anticipated savings, reaching approximately $400 million.., the area around the Science Centre is being developed for the upcoming
Ontario Line, which will pass nearby in an overhead track. Deforestation and land development work has been occurring at the site.
The station for the line and for
Line 5 Eglinton that were originally to be known as "Science Centre station" have been renamed to "Don Valley Station". Security presence, as well as construction and repairs on the roof of the building have also been noticed, though Infrastructure Ontario stated that direct roof access for snow removal was "unsafe" following record snowfalls in early 2026. All of this continues with no clear plan from the province for what will become of the original building. Following heavy snowfall in January 2026, renewed calls to reopen or find alternative use for the building occurred, with continued refusal from the government of Ontario. This followed previous reports that continued maintenance work was occurring at the building and plans for a temporary site at the Toronto
Harbourfront centre. No confirmed usage for the original building has been announced as of 2026. In February 2026, Premier Ford unveiled the designs of the new building and announced that a contract had been awarded for its construction. It will cost an estimated $1 billion and will be smaller than the original facility, with a footprint of about . ==Original grounds==