Atty. Sean W. Plat

Atty. Sean W. Plat

Sean was called to the bar in 1997 and has been practicing exclusively in the area of family law for more than 26 years. He has expertise in complex property and spousal/child support cases, marriage contracts and cohabitation agreements, and he brings a practical yet empathic approach to high conflict parenting cases.

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Profile Summary

About Sean W. Plat at a glance

Sean W. Plat is a family law attorney based in Guelph, Ontario, practicing at Plat Simionati LLP. Recognitions include Best Lawyers in America — Family Law (2026). Serands clients in Guelph, ON and the surrounding metropolitan area.

Verified attorney profile · Updated June 2026

About

  • Sean was called to the bar in 1997 and has been practicing exclusively in the area of family law for more than 26 years
  • He has expertise in complex property and spousal/child support cases, marriage contracts and cohabitation agreements, and he brings a practical yet empathic approach to high conflict parenting cases
  • His expertise extends to married and unmarried spouses and to the LGBTQ+ community
  • Sean has successfully advanced matters in all levels of court in Ontario
  • In addition to resolving family law issues by way of traditional methods such as negotiation and/or litigation, he also has extensive experience in acting for clients in alternative dispute resolution methods including mediation, arbitration and collaborative family law
  • Sean has completed his training as a mediator and is able to offer his experience and skillset to parties who wish to resolve their issues outside of court with the assistance of a knowledgeable and effective mediator
  • Sean was born and raised in the City of Guelph and attended law school at Queen’s University after obtaining his undergraduate degree at the University of Guelph
  • He joined Kearns McKinnon in 1998
  • Kearns McKinnon merged with Miller Thomson LLP in 2003, where Sean was a partner for 16 years
  • In 2022 Sean and Taryn founded Plat Simionati LLP with the goal of combining their strengths to provide their clients with strong, practical and efficient family law representation

Practice Areas Explained

Sean W. Plat's Areas of Practice

Each practice area below reflects the types of cases Sean W. Plat handles, with a brief overview of what that area of law covers.

Family Law

Family law attorneys handle divorce, child custody, child support, adoption, prenups, and protective orders. Find verified family lawyers near you.

Sean W. Plat is one of 187,066 family law attorneys indexed nationally. Browse family law attorneys in Ontario →

Jurisdictional Context

Why local counsel matters in Ontario

Practicing law in Ontario. Legal matters in Ontario are governed by state-specific rules of civil and criminal procedure, statutes of limitations, and substantive law. Cases originating in Guelph are typically filed in the local municipal court or the appropriate Ontario state district court, depending on subject matter and amount in controversy. An attorney licensed in Ontario brings working knowledge of local procedural deadlines, judicial practices in this andnue, and the substantive law that applies to cases brought here. Out-of-state attorneys generally cannot represent clients in Ontario courts without local counsel or pro hac vice admission.

Looking for additional Ontario attorneys? Browse all attorneys in Guelph or all attorneys in Ontario.

Frequently Asked

Common questions about Sean W. Plat

Where is Sean W. Plat's law office located?
Sean W. Plat's law practice is located in Guelph, Ontario. The firm is Plat Simionati LLP. You can contact the office directly through this profile page.
What practice areas does Sean W. Plat handle?
Sean W. Plat focuses on family law. Each practice area listed reflects experience handling cases of that type in Ontario.
How can I contact Sean W. Plat for a consultation?
You can contact Sean W. Plat directly through this profile page. Click "Ask the Attorney" to submit a question, or "Schedule a Consultation" to book a meeting. Most claimed-profile attorneys respond within one business day.
What awards or recognition has Sean W. Plat received?
Sean W. Plat's notable recognition includes: Best Lawyers in America — Family Law.

Practice Areas

Awards

Best Lawyers in America — Family Law
- 2026

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