A method of handling a communication session, comprising: at a wireless mobile communications device: receiving (408, 506) an indication of current signal strength of an access point (312, 322a) for a wireless local area network, "WLAN", (310, 320); retrieving a signal strength threshold (D2, Table 10; D1, Table 10; 180, 181, 182) associated with said access point (312, 322a); if said communication session is currently carried by a cellular network and said current signal strength exceeds said signal strength threshold (D2, Table 10; 182): attempting to switch said communication session from said cellular network to said WLAN (312, 322a); determining whether said attempting to switch is successful; based on whether said attempting to switch is successful, adjusting a failure rate (175d; Table 3) associated with said access point (312, 322a); if it is determined that said attempting to switch is successful, adjusting a number of successful attempts; determining whether said failure rate is below a minimum threshold; and selectively decreasing said signal strength threshold if said failure rate is below the minimum threshold for said failure rate (Rule 3, Table 5); adjusting a number of successful attempts per minute based on the number of successful attempts; and adjusting said signal strength threshold associated with said access point to increase said signal strength threshold if the number of successful attempts per minute exceeds a maximum threshold; wherein said failure rate is based on an average switch failure rate, at said wireless mobile communications device, from said cellular network to said access point (312, 322a) of said WLAN (310, 320) within a preceding time window. receiving (408, 506) an indication of current signal strength of an access point (312, 322a) for a wireless local area network, "WLAN", (310, 320); retrieving a signal strength threshold (D2, Table 10; D1, Table 10; 180, 181, 182) associated with said access point (312, 322a); if said communication session is currently carried by a cellular network and said current signal strength exceeds said signal strength threshold (D2, Table 10; 182): attempting to switch said communication session from said cellular network to said WLAN (312, 322a); determining whether said attempting to switch is successful; based on whether said attempting to switch is successful, adjusting a failure rate (175d; Table 3) associated with said access point (312, 322a); if it is determined that said attempting to switch is successful, adjusting a number of successful attempts; determining whether said failure rate is below a minimum threshold; and selectively decreasing said signal strength threshold if said failure rate is below the minimum threshold for said failure rate (Rule 3, Table 5); adjusting a number of successful attempts per minute based on the number of successful attempts; and adjusting said signal strength threshold associated with said access point to increase said signal strength threshold if the number of successful attempts per minute exceeds a maximum threshold; wherein said failure rate is based on an average switch failure rate, at said wireless mobile communications device, from said cellular network to said access point (312, 322a) of said WLAN (310, 320) within a preceding time window. attempting to switch said communication session from said cellular network to said WLAN (312, 322a); determining whether said attempting to switch is successful; based on whether said attempting to switch is successful, adjusting a failure rate (175d; Table 3) associated with said access point (312, 322a); if it is determined that said attempting to switch is successful, adjusting a number of successful attempts; determining whether said failure rate is below a minimum threshold; and selectively decreasing said signal strength threshold if said failure rate is below the minimum threshold for said failure rate (Rule 3, Table 5); adjusting a number of successful attempts; determining whether said failure rate is below a minimum threshold; and selectively decreasing said signal strength threshold if said failure rate is below the minimum threshold for said failure rate (Rule 3, Table 5); adjusting a number of successful attempts per minute based on the number of successful attempts; and adjusting said signal strength threshold associated with said access point to increase said signal strength threshold if the number of successful attempts per minute exceeds a maximum threshold; wherein said failure rate is based on an average switch failure rate, at said wireless mobile communications device, from said cellular network to said access point (312, 322a) of said WLAN (310, 320) within a preceding time window.