Public construction bidding in Ontario: the complete guide (2026)

Ontario buys more construction than any other province. The 2026 budget carries a capital plan of more than $210 billion over ten years - roughly $63 billion for transit, $31 billion for highways, $64 billion for hospitals and health infrastructure - and that is before Toronto's own $63-billion ten-year capital plan and hundreds of municipalities, school boards, and universities buying on top of it. The work is not the problem.

The problem is that Ontario's public work is scattered across more portals than any other province's, and the buyers - not the platforms - decide where each tender posts. This is the complete guide to bidding public construction work in Ontario: where the opportunities actually live, how the process works, what you need to be eligible, and where bids are won and lost. Each section links to a deeper guide where one exists.

Ontario public tenders, by the numbers

A snapshot from Cornerstone's own tender database (as of July 12, 2026 - these figures shift daily as boards post and close):

| Metric | Ontario | |---|---| | Public tenders tracked | 4,200+ | | Open right now | ~530 | | New in the last 30 days | ~1,190 | | Median window from posting to close | ~22 days (a quarter close within ~16) | | Leading trade categories | Mechanical and electrical lead the board, with bridges, paving, and underground and civil infrastructure close behind |

The median Ontario tender gives you about three weeks from when it appears to when it closes, and about a quarter close inside 16 days. That short window is the real reason small teams lose winnable work - not price, but the time it takes to find the right tender across five-plus portals and respond well. The rest of this guide is about closing that gap.

Want the current list? Browse open Ontario tenders, updated daily - free, no account needed. For how Ontario stacks up against Alberta, B.C., and Saskatchewan on the same day, see the live board, by province and trade.

From the founder: I'm a pipelayer in Edmonton, so I won't pretend Ontario is my home turf. But the pattern I built Cornerstone around is at its sharpest there: more buyers running more portals than anywhere else in the country, which means the winnable tender is that much more likely to post somewhere you weren't watching that morning. A three-week median window doesn't forgive a week spent finding out the job existed. If you ever want to talk through a bid, write to me at joseph@cornerstonecontracts.com - I read every one. - Joseph Morrison, Founder, Cornerstone Contracts (Edmonton)

Figures are aggregates from the public postings Cornerstone ingests across the boards that carry Ontario work (MERX, Biddingo, CanadaBuys, the City of Toronto's public bid data, and sector feeds such as school boards, health, and transit). They describe what we track, not the entire market - Ontario work also moves through buyer-specific portals and invitation-based prequalification pools - and they change as tenders open and close.

1. Where Ontario tenders are posted: watch buyers, not portals

There is no single tender board, and in Ontario even the platforms change hands and migrate. The durable mental model is to learn where each buyer posts:

• Ontario Tenders Portal (OTP) - the province's official site, run for Supply Ontario on the Jaggaer platform. Government of Ontario ministries and many broader-public-sector entities post here. Vendor registration is free.
• Infrastructure Ontario and Metrolinx post on MERX, not OTP. The province's two heaviest construction buyers - IO for hospitals, courthouses, and the subway program; Metrolinx for GO and transit expansion - run their procurements through MERX, including their vendor-of-record streams. If you only watch the official provincial portal, you miss the biggest provincial work.
• City of Toronto - advertises through its own Toronto Bids Portal and transacts on SAP Ariba (suppliers register on the SAP Business Network). Toronto procured roughly $3 billion in 2024 and is carrying the largest capital plan in its history. See our Toronto tenders guide.
• City of Ottawa - goods and services at $125,000 and over post on MERX, but construction contracts at $125,000 and over are advertised on the Ottawa Construction Association's bulletin board, with smaller work through the City's own quotation process. That construction carve-out is the single clearest illustration of how fragmented this market is. See our Ottawa tenders guide.
• bids&tenders - the default platform for much of municipal Ontario: Hamilton, London, Kitchener, Guelph, Barrie, Burlington, Vaughan, the Peel, Halton, York, and Niagara regions, and major school boards (TDSB, TCDSB, YRDSB) each run their own branded portal on it. See our Hamilton tenders guide for how these portals work in practice.
• Biddingo - a second aggregator cluster: Windsor, Toronto Community Housing, and university construction work (the University of Toronto's construction arm posts here) among others.
• Hospitals post their own capital work individually, and their major redevelopments run through Infrastructure Ontario on MERX.
• CanadaBuys - the federal system, for federal buildings, bases, and parks work in Ontario - with one exception that matters for construction: Defence Construction Canada posts on MERX. See our CanadaBuys guide for contractors.

Two things keep this honest. First, the Broader Public Sector Procurement Directive is why the work is findable at all: BPS organizations must run open competition on an accessible electronic system for purchases of $100,000 and over. Second, the platform layer is churning - Mississauga is moving from bids&tenders to Bonfire in 2026, the OECM buying group already did, and bids&tenders itself changed owners in late 2025 - so bookmark each buyer's procurement page, not just today's platform URL.

The real problem isn't access - it's coverage. In Alberta, watching several portals is a chore; in Ontario, five portals is the entry fee, and the large majority of postings that don't fit your trade or size bury the few that do.

2. How the process works: the four tender types

Public bodies use different document types depending on what they're buying and how much discretion they want. Knowing which one you're holding tells you where to spend your effort:

1. RFQ (Request for Quotations) - lowest compliant price wins. Common for straightforward, well-defined work below open-tender thresholds.
2. RFT / ITT (Request for Tenders / Invitation to Tender) - a firm-priced bid on a fully specified scope, awarded to the lowest compliant bid. This is the workhorse of Ontario municipal construction; compliance and bonding decide who is even scored.
3. RFP (Request for Proposals) - scored on rated criteria (methodology, team, past performance) and price. This is where proposal quality moves the needle.
4. RFQual / Pre-Qualification - a two-stage process common on larger Ontario work: you qualify first, then only prequalified firms are invited to bid. Miss the prequalification window and the project is closed to you for its duration.

An RFT rewards a clean, competitive number. An RFP rewards a specific, well-argued proposal. For the document types in depth, see the four tender types explained, and for the general playbook, how to win a construction tender in Canada.

3. What you need to be eligible: certification, clearance, bonding

This is where technically strong bids are quietly eliminated before they're ever scored - and Ontario's gates are its own:

• A certified health and safety management system. The City of Toronto requires one on all construction contracts regardless of value; Metrolinx disqualifies bids that aren't COR-certified at submission; the TTC requires certification on all contracts. IHSA is Ontario's authority for COR 2020. And since 2026, provincial rules require public bodies that demand certification to accept any system accredited by the Chief Prevention Officer - COR 2020, SOSE, or ISO 45001 - so you have options, but none of them are fast. Start months before you bid.
• WSIB clearance. Compulsory coverage applies broadly in Ontario construction, and a principal who hires you must obtain a clearance certificate before work begins - working without one is an offence for both parties. Clearances are valid for up to 90 days and renewable online. Have yours current at bid time. Our insurance and WCB requirements guide covers the provincial equivalents side by side.
• Compulsory trades. Ontario certifies trades through Skilled Trades Ontario, and 23 trades are compulsory - including construction and maintenance electrician (309A), plumber (306A), steamfitter (307A), sheet metal worker (308A), refrigeration and A/C systems mechanic (313A), and mobile and tower crane operators. Working in one requires a Certificate of Qualification or registered apprenticeship.
• Electrical contractors need an ECRA/ESA licence. Bidding electrical work in Ontario requires an Electrical Contractor licence from the Electrical Safety Authority - a Master Electrician on staff, at least $2 million in liability insurance, and WSIB registration. A Master Electrician certificate alone does not let you contract.
• Bonding - and in Ontario, some of it is statutory. Under the Construction Act, public contracts of $500,000 or more require a performance bond and a labour and material payment bond, each covering at least 50 percent of the contract price. Bid bonds (commonly around 10 percent) and agreements to bond are routine at submission on municipal work. Your aggregate bonding capacity caps the size of work you can pursue, so establish a surety relationship early - the mechanics in our bid bonds and surety guide are written for Alberta but travel: the instruments are the same, and Ontario adds the statutory layer above.
• Insurance. Commercial general liability (commonly $2 million, scaling to $5 million or more on larger work) and other coverages are typically mandatory, with the owner named as additional insured.

Treat compliance as a system you maintain, not a checklist you scramble through on deadline day. On lowest-compliant-bid work - most Ontario municipal construction - a compliance miss doesn't cost you points; it removes you from the competition entirely.

4. Getting paid, and the rules that widen (and narrow) your market

Prompt payment is law in Ontario - and it has teeth. Ontario ran Canada's first prompt-payment regime (in force since October 2019) under the Construction Act: an owner must pay a proper invoice within 28 days or deliver a notice of non-payment within 14, you must pay your subs within 7 days of being paid, and disputes go to fast interim adjudication through ODACC. Amendments in force since January 1, 2026 strengthen it further: invoices are deemed proper unless the owner flags deficiencies in writing within 7 days, holdback must now be released annually, and adjudication can be started up to 90 days after contract completion. Know your rights before a payment stalls - our prompt-payment guide covers the regime in detail.

Trade agreements set who can bid what. Above thresholds, Ontario public bodies must post openly and cannot favour local firms:

• CFTA opens Ontario construction procurement across Canada - for 2026-27, at $139,000 for provincial ministries and agencies, $347,400 for the MASH sector (municipalities, school boards, academic and health entities), and about $6.9 million for Crown corporations.
• CETA additionally opens larger work (construction at roughly $9.2 million and up, including municipal) to European suppliers.
• The Ontario-Quebec Trade and Cooperation Agreement gives Ontario and Quebec firms reciprocal access to each other's public work - the two-way street that matters most along the Ottawa River. (The New West Partnership the Western provinces use does not apply here.)
• Below those thresholds, 2026 changed the game in your favour if you're local: the Buy Ontario Procurement Directive (in force April 2026, extended to municipal capital infrastructure that May) requires public buyers to prefer Ontario businesses on smaller procurements, then Canadian businesses up to higher tiers - and excludes US businesses from covered procurements outright. For an Ontario contractor, small public work got structurally friendlier this year.

Some public work runs the other way - reserved for Indigenous businesses through set-asides and Ontario's Indigenous procurement program; see Indigenous and set-aside procurement in Canada.

5. Where bids are actually won and lost

Small and mid-sized contractors win a minority of the competitive public bids they enter, and most losses trace to preventable mistakes rather than price:

• Compliance misses on lowest-compliant-bid work. On an RFT, a missing bond consent or an unsigned addendum acknowledgment sets your envelope aside unread. Addenda deserve particular respect - see tender addenda and staying compliant.
• Generic positioning on RFPs. Evaluators reading a stack of "proven, mission-focused team" proposals are looking for specifics - why you are the lowest-risk choice for this job.
• Proposal fatigue. A thorough RFP response can eat three weeks against a 30-day clock, so under-resourced teams cut corners on the sections that win points.

The fix is discipline, not volume: centralize discovery so you stop missing fits, qualify ruthlessly to the few opportunities a month you can genuinely win (our go/no-go framework is the two-minute version), read the evaluation criteria first, and make compliance your first pass instead of your last. See also how to structure a winning bid proposal, our construction bid proposal template, and why contractors lose government bids.

6. A note on trades

Public work isn't only for general contractors. Electrical, mechanical, civil, concrete, and specialty trades all bid Ontario public tenders directly and as subcontractors on larger packages. The same rules apply - find the fits, meet the mandatory requirements, present capability specifically - but Ontario's compulsory-trade certification and the ESA licensing regime mean trade eligibility is checked harder here than almost anywhere: the right ticket, in the right classification, current. The closer your profile reflects your actual specialties, the cleaner your opportunity list.

7. Doing this without burning your mornings

Everything above is doable by hand. It's just slow - and in Ontario, slower than anywhere else: the same morning routine that covers one portal in Saskatchewan covers a fraction of the boards that carry Ontario work.

Cornerstone Contracts was built for this. It scans the boards that carry Ontario's public construction work every day, scores each posting against your trade, geography, and project size, and drafts a compliance-aware bid proposal tailored to the specific tender - so discovery and the first draft are done before your coffee's cold. The matching is deterministic and explainable, not a black box; here's exactly how it scores each opportunity. You can start free and see your matched Ontario opportunities today - spend your time building, not searching.

This guide is general information, not procurement or legal advice. Portal arrangements, thresholds, certifications, and requirements change - always confirm current details in the official tender documents and with the relevant authorities.