The largest brokerages in Sarnia
3 offices, 165 agents counted at the 2026-08-07 scan. REMAX Sarnia Realty Inc leads with 115 agents — 69.7% of the tracked roster, ahead of Coldwell Banker Southwest Realty, Brokerage at 45. The local market is unusually concentrated — three offices hold most of it (top three hold 100%).
Every office we track in Sarnia
| # | Office | Network | Agents | Share |
|---|---|---|---|---|
| 1 | REMAX Sarnia Realty Inc | RE/MAX | 115 | 69.7% |
| 2 | Coldwell Banker Southwest Realty, Brokerage | Coldwell Banker | 45 | 27.3% |
| 3 | Coldwell Banker COMMERCIAL Southwest Realty. Brokerage | Coldwell Banker | 5 | 3% |
Offices with fewer than 10 agents appear in this table but don't get their own page. Across the 115 Sarnia agents whose sites we check, 121.7% list a website of their own (national 56.7%).
Network mix in Sarnia
Coverage: these are the 2 national networks we scrape — about 44.4% of Canadian REALTORS® nationally. Independents and brokerages outside those networks aren't counted, so read this as the largest offices among the networks we track in Sarnia. Methodology →
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