Skilled Trades Ontario is the agency behind almost every credential an Ontario tradesperson carries, from an apprentice's Registered Training Agreement to the wallet card a licensed electrician shows on site. If you are planning a trades career in the province or hiring for one, its rules decide who can legally do the work, how long training takes, and what a candidate's paperwork should look like. This guide pulls the key numbers and steps from Skilled Trades Ontario's own published material so you can act on them today.
Key facts (from Skilled Trades Ontario, checked October 2026)
- Skilled Trades Ontario (STO) was created under the Building Opportunities in the Skilled Trades Act, 2021 and took over from the Ontario College of Trades on January 1, 2022.
- Its Apprenticeship Programs Quick Facts Chart (updated June 2026) lists 144 trades. About two dozen are compulsory; the rest are non-compulsory.
- A 309A Construction and Maintenance Electrician apprenticeship is 9,000 hours: 7,950 on the job and 1,050 in school.
- The certifying exam costs $150 plus HST per attempt. Apprentices with a completed training agreement do not pay for their first attempt.
- Journeypersons in compulsory trades pay an annual Certificate of Qualification renewal of $60 plus HST.
- Anyone can check a tradesperson's status on the free STO Public Register.
What Skilled Trades Ontario Does Now
Responsibility for Ontario's trades system has moved twice in five years, which is why so much online advice is out of date.
From the College of Trades to STO
The Ontario College of Trades was wound down at the end of 2021. STO took over trade standards, curriculum, certifying exams, Certificates of Qualification and the Public Register. Certificates issued before January 1, 2022 remain valid.
Apprenticeship registration moved too
For years, Registered Training Agreements were handled by the Ministry of Labour, Immigration, Training and Skills Development (MLITSD) through Employment Ontario apprenticeship offices. STO is now the first point of contact for apprenticeship services. Sponsors register and apprentices apply through the Skilled Trades Ontario Portal, and the signed agreement appears in the apprentice's Portal account. MLITSD still funds in-school training and runs Employment Ontario, which remains the place to ask about grants and employer training funding (1-800-387-5656).
Who to call for what
- Exams, certificates, the Public Register and apprenticeship registration: Skilled Trades Ontario, 647-847-3000 or 1-855-299-0028 toll-free in Ontario, weekdays 7 a.m. to 7 p.m.
- Grants, employment services and hiring supports: Employment Ontario.
- Electrical contractor licensing: the Electrical Safety Authority (ESA), which is separate from STO.
- Gas technician certificates (G3, G2, G1): the Technical Standards and Safety Authority (TSSA), which is also separate.
Compulsory vs Non-Compulsory Trades
A footnote in STO's chart states the rule plainly: in a compulsory trade, you must be a registered apprentice, a Provisional Certificate of Qualification holder or a Certificate of Qualification holder to legally do the work.
The compulsory list in practice
Most compulsory trades are in construction electrical, piping, HVAC and motive power. They include Construction and Maintenance Electrician (309A), Domestic and Rural Electrician (309C), Plumber (306A), Steamfitter (307A), Sheet Metal Worker (308A), Refrigeration and Air Conditioning Systems Mechanic (313A), Residential Air Conditioning Systems Mechanic (313D), Automotive Service Technician (310S), Auto Body and Collision Damage Repairer (310B) and Hairstylist (332A).
Big non-compulsory trades
General Carpenter (403A), Welder (456A), Industrial Mechanic Millwright (433A) and Industrial Electrician (442A) are all non-compulsory, but each has a certifying exam and is Red Seal eligible. A Certificate of Qualification is not legally required in these trades, but many industrial employers and union halls still ask for one.
Hours-based ratio trades
STO also flags certain programs as hours-based. In these trades, the apprentice must log the full prescribed on-the-job hours, and a ratio of 1 journeyperson to 1 apprentice must be maintained at all times. 309A, 306A, 307A, 308A, 313A and 403A are all on that list. For a contractor, the ratio limits how many apprentices a crew can carry, so plan for it before taking on another first-year apprentice.
Apprenticeship Hours for Common Ontario Trades
All figures below come from STO's Apprenticeship Programs Quick Facts Chart, updated June 2026. In-school curriculum hours are revised from time to time, so check the chart before you plan around a number.
Construction and mechanical
- Construction and Maintenance Electrician (309A): 9,000 total hours, 4 in-school levels, Grade 10 entry.
- Plumber (306A): 9,000 hours (8,280 on the job, 720 in school), Grade 10 entry.
- Steamfitter (307A) and Sheet Metal Worker (308A): 9,000 hours each.
- Refrigeration and Air Conditioning Systems Mechanic (313A): 9,000 hours.
- General Carpenter (403A): 7,200 hours (6,480 on the job, 720 in school).
Industrial and motive power
- Industrial Mechanic Millwright (433A): 8,000 hours, Grade 12 entry.
- Industrial Electrician (442A): 9,000 hours, Grade 12 entry.
- Welder (456A): 6,000 hours (5,280 on the job, 720 in school), Grade 12 entry.
- Automotive Service Technician (310S): 7,220 hours, Grade 12 entry.
What those hours mean in years
STO says apprenticeships take 2 to 5 years, with about 80 percent of the time spent working and 20 percent in class. A typical pattern is a year or more on the job, followed by an 8 to 12 week block of in-school training at a college or union training centre. At full-time hours, a 9,000-hour trade takes close to five years.
How to Start an Apprenticeship in Ontario
Finding a sponsor is the hardest step. You do not need to be enrolled in school to begin.
Step 1: Get ready, or test a trade first
High school students who are entering Grade 11 and are at least 16 can join the Ontario Youth Apprenticeship Program (OYAP) through their school board. Adults can look at government-funded Pre-Apprenticeship programs, which last up to a year and may include Level 1 in-school training. College certificate and diploma programs can also shorten some apprenticeships.
Step 2: Find a sponsor
Sponsors are usually employers, but group sponsors and unions also register apprentices. Options in Ontario include:
- Union halls and training centres, such as IBEW Local 353 for electricians in the Toronto area, UA Local 46 for plumbers and steamfitters in Toronto, and Carpenters' Union Local 27, which runs a training centre in Woodbridge.
- Group sponsors such as Merit Ontario, which can act as the sponsor and match apprentices with open-shop contractors.
- Direct applications to contractors, manufacturers and facility operators that post apprentice openings.
Step 3: Register the training agreement
Your sponsor must be approved first, either through the STO Portal or with a paper application. Once the sponsor is approved, you both sign a Training Agreement and register it with STO. Apprentices aged 16 or 17 use the paper form, which a parent or guardian must sign.
Step 4: Attend in-school training
When it is time for each level, you attend a Training Delivery Agent. Mohawk College's Stoney Creek campus, for example, publishes block dates for 403A, 433A and 309A levels running through spring 2027. George Brown College, Humber Polytechnic and Centennial College also deliver apprenticeship levels in the Toronto area.
Getting Certified: Exams, Fees and the Public Register
Finishing your apprenticeship
When you submit your completion form, STO issues a Certificate of Apprenticeship. In a trade with a certifying exam, STO also issues a Provisional Certificate of Qualification automatically. It is valid for one year, so you can keep working while you prepare for the exam.
Booking and paying for the exam
The exam fee is $150 plus HST, paid in the STO Portal (see STO's exam scheduling page). If you fail, you must wait 30 days and pay the fee again before you retake it. STO has said it is moving certifying exam delivery in-house as of February 2026, so confirm the booking steps in the Portal instead of relying on older guides.
Experienced workers without an Ontario apprenticeship
If you trained elsewhere, a Trade Equivalency Assessment ($235 plus HST) decides whether you can challenge the exam. Your experience must at least equal the program's total training hours. A reassessment costs $100 plus HST.
Verifying a candidate on the Public Register
The STO Public Register shows certificate status, including Provisional Certificates. For a hire in a compulsory trade, checking the register before the first shift takes a minute and protects you if an inspector asks. Ask the candidate for their trade code and certificate number, then search.
Using SkilledTradeJobs.ca for Ontario Roles
SkilledTradeJobs.ca is a Canada-focused job board for the trades. It helps most when employers and job seekers include the details above in their postings and profiles.
For employers
Put the trade code in the job title (for example 309A, 306A or 433A). State whether you need a Certificate of Qualification, a Provisional Certificate or a registered apprentice, and say what level an apprentice should be at. If you work in an hours-based trade, mention whether your ratio leaves room for a new apprentice. You can post a role at SkilledTradeJobs.ca for employers.
For job seekers
Start your profile with your trade code, certificate number and hours logged, and say whether you are looking for a sponsor. Ontario roles, including skilled trade jobs in Toronto, are listed at SkilledTradeJobs.ca for job seekers.
FAQ
Do I register my apprenticeship with Skilled Trades Ontario or the ministry?
With Skilled Trades Ontario. Sponsors and apprentices now register through the STO Portal. Employment Ontario, run by MLITSD, still handles grants and employment services.
How many hours is the 309A electrician apprenticeship?
It is 9,000 hours in total: 7,950 hours on the job and 1,050 hours of in-school training across four levels, according to STO's June 2026 chart.
What does the certifying exam cost?
It costs $150 plus HST per attempt. Apprentices with a completed training agreement get their first attempt free, and you must wait 30 days before a retake.
Can I work as a welder or carpenter in Ontario without a certificate?
Yes. Welder (456A) and General Carpenter (403A) are non-compulsory trades. Many employers still prefer certified candidates, and both trades are Red Seal eligible.
How do employers confirm someone's certificate?
Search the free Skilled Trades Ontario Public Register by name or certificate number. It also shows Provisional Certificates of Qualification.
Does a Certificate of Qualification expire?
In compulsory trades, journeypersons must renew every year for $60 plus HST. They receive an expiry sticker for their wallet card.
Find or Fill Your Next Ontario Trades Role
Skilled Trades Ontario sets the hours, exams and certificates, but the work happens on sites, in plants and in shops across the province. Whether you are hiring or job hunting, SkilledTradeJobs.ca serves both sides of the market. Employers can review pricing and post a role at SkilledTradeJobs.ca for employers. Job seekers can browse openings and create a profile at SkilledTradeJobs.ca for job seekers.