Voice call continuity is provided for calls that are carried over a hybrid network infrastructure in which access connections are distributed over loosely coupled network portions including a backend network such as a core VoIP (Voice over Internet Protocol) service network, one or more cellular mobile networks, and a public switched telephone network ("PSTN"). The calls are routed through the core VoIP network regardless of their points of origination or termination in other network portions so that signaling and call context are anchored in the core VoIP network. The conditions under which user equipment operate are continuously monitored so that when a connection is determined to have been unacceptably degraded or is likely to be interrupted, and/or a more optimal connection is available, a handover of the call to another connection is initiated so that call continuity is maintained using the lowest cost connection that provides acceptable call quality.