Provided herein are apparatus and method for signal RAN-assisted codec adaptation capabilities via IMS. An apparatus for a UE includes a RF interface to receive an SDP offer message from the remote UE, the SDP offer message including a first dedicated SDP attribute parameter to indicate support of ANBR capability of the remote UE; and processor circuitry. The processor circuitry is to decode the SDP offer message to determine the support of ANBR capability of the remote UE; encode an SDP answer message in response to the SDP offer message, the SDP answer message including a second dedicated SDP attribute parameter to indicate support of ANBR capability of the UE; and cause transmission of the SDP answer message to the remote UE. Other embodiments may also be disclosed and claimed.