Toronto transit riders can stay plugged in at more subway stations as the TTC has expanded free WiFi to another four stations.

The service is now offered at Union, King, Queen and Dundas stations. This is in addition to St. George, Bay, Bloor-Yonge, Wellesley and College stations.

Users will be able to browse the web, check their email and watch for real-time transit alerts in all public areas of the stations, including platforms, mezzanines, walkways and stairs.

The TTC, in partnership with BAI Canada, has been rolling out free public WiFi since 2013. All stations on the downtown lower-loop, and Spadina Station, are expected to have WiFi installed in advance of the Toronto 2015 Pan Am Games, which begin in July.

BAI, which also provides cellular and WiFi coverage for mass transit systems in New York and Hong Kong, won a contract in December 2012 to develop WiFi and cellular services for Toronto's subway network. The $25 million, 20-year-deal allows BAI to generate revenue from ads shown to users before they connect.

The TTC expects to establish wireless connectivity in all subway stations in the next three years. Stations will also be outfitted to provide cellular service.