What is the area code(s) for Ontario state? The area code(s) of Ontario is 226, 249, 289, 343, 365, 416, 437, 519, 613, 647, 705, 807, 905, Cities of Ontario OrangevilleBracebridgeAjaxClarence-RocklandHamiltonTorontoLondonPerthPeterboroughDrydenMarkham Click here to find Canada Area Code List