In general, this disclosure describes techniques for initiating a communication session when a user indicates she or he is available to participate in the communication session. In one example, a method includes receiving, by a first communication device, an indication that a user is available to participate in a communication session that enables communication between different communication devices. Responsive to receiving the at least one signal, the communication session may be initiated in an inactive mode at the first communication device. The first communication device may receive a request from a second communication device to participate in the communication session. Responsive to receiving the request, the communication session may be switched from the inactive mode to an active mode.