Skilled Trades Ontario: Prometric STO Certification Exam

At Pathways4U, we understand how important it is for skilled trades professionals to earn their certification in Ontario. The Skilled Trades Ontario (STO) exam, administered by Prometric, is a key step in many trades for obtaining a Certificate of Qualification, which validates your expertise and opens doors to better work opportunities.

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What Is Skilled Trades Ontario (STO)?

Skilled Trades Ontario (STO) is the provincial authority responsible for apprenticeship registrations and certification exams. As of April 2, 2025, STO officially manages all certifying exams through Prometric. A Certificate of Qualification proves that you have successfully passed the required exam for your trade.

For those in Red Seal‐designated trades, you may be writing the interprovincial Red Seal exam; for others, a provincial STO exam applies.

How the STO Exam Works

Prometric serves as the third-party testing provider for STO exams. To schedule your exam, you must first receive an Authorization to Test Letter from STO. This letter contains important information like your eligibility number, which is needed at the Pathways test centre. Skilled Trades Ontario Exams typically last up to four hours and consist of 90 to 150 multiple-choice questions. You must score at least 70% to pass. If you require accommodations for disabilities, you can formally request them ahead of time through STO.

Why Certification Matters

A Certificate of Qualification from STO acknowledges your professional competence. In compulsory trades, it is required to legally practice in Ontario. Even in non-compulsory trades, certification enhances your marketability and proves your dedication and skill. With more than 140 skilled trades in Ontario, certification is often a key differentiator.

  • Preparing for the Exam

    Preparation is critical to success. Skilled Trades Ontario provides a variety of exam resources, including sample exams, study guides, and preparation courses. Their Exam Preparation Guide explains exam structure, recommended study practices, and test-taking strategies. Many candidates also use apprenticeship training materials and trade textbooks to prepare.

  • Exam Day Checklist

    • Bring printed Authorization to Test Letter and valid photo ID (name must match)
    • Leave personal items (phones, wallets, jackets, food, drinks) in the locker
    • Follow all instructions from the test administrator
    • No electronic devices allowed during the exam

  • After You Pass

    If you pass the STO exam, you will receive your Certificate of Qualification from Skilled Trades Ontario. For those who don’t pass on the first try, be aware of STO’s retake policies. Check their resources or reach out to us at Pathways for guidance.

Book Your Skilled Trades Ontario Certification Exam

Take the next step in your skilled trade career. Schedule your STO exam at Pathways and enjoy a secure, comfortable testing environment.For more information visit www.prometric.com/exams/sto.

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