Examples disclosed herein provide methods and systems for selecting Internet Protocol addresses for Session Initiation Protocol (SIP) communications. In at least one implementation, a method of operating a communication network utilizing a session initiation protocol (SIP) is provided. The method performed within a second communication device includes receiving a SIP invite from a first communication device, and determining a source IP address for the second communication device, using an IP address for a third communication device as a destination address within a source address selection algorithm (SASA) function. The method further includes adding a Via header within the SIP invite to include the SASA determined source IP address for the second communication device, adding a Record-Route header within the SIP invite to include the SASA determined source IP address for the second communication device, and transferring the modified SIP invite to the third communication device.