St. Catharines is the retail heart of Niagara’s fuel market, with its stations strung along Ontario Street, Welland Avenue, Fourth Avenue and the QEW interchanges, plus the Thorold stations just up the escarpment. The Fourth Avenue big-box node — where the Costco gas bar sits — is the price anchor: everything nearby competes against the warehouse floor, making that end of town the dependable cheap pocket.
QEW commuters between Hamilton and the border have room to optimize, because Niagara prices don’t always move in step with the rest of the Golden Horseshoe. The list below ranks every St. Catharines and Thorold station we track by current price, refreshed hourly — Niagara Falls has its own page for the tourist-corridor comparison.