A mobile switches operation for communications from a wireless wide area network (WWAN) to a wireless local area network (WLAN) in an efficient manner. While providing operation for communications in the WWAN, the mobile device continually maintains visited cell site history information which is indicative of visited cell sites of the WWAN that served the mobile device over a moving time period of its operation. The mobile device continually monitors this information to identify whether it has been contained within a local geographic region over the moving time period. When the mobile device is identified to have been contained within the local geographic region, it is permitted to operate for communications with the WLAN, and may enable its WLAN radio transceiver and select the WLAN for communications.