New area codes are coming across Canada Tell Toronto-area residents you live "in the 905" or "in the 416," and chances are they know what you're talking about. But as of March 25, things get slightly more complicated. As is happening elsewhere in Canada, the era of mass cellphones has left the designated-number system full to overflowing, and soon there won't be any more 416s or 905s to assign. Help, however, is on the way, in the shape of additional new area codes that will allow up to seven million new numbers to be created, Canada-wide. In Toronto, the 416 and 647 area codes will be augmented by a new prefix: 437. And within the mostly suburban domain of 905 and 289, the new three-digit face on the block will be 365. Similar area-code additions will take effect in northern Ontario, Quebec and Manitoba. The changes were announced Wednesday by the Telecommunications Alliance, a network of service providers. With the approval of the Canadian Radio-Television and Telecommunications Commission, some will be implemented late next month and the rest will follow.