Systems and methods are disclosed that provide notification of waiting voicemail messages between different types of communication networks. A first communication network as described herein includes a voicemail server to store voicemail messages for a user of a communication device. A second communication network provides phone service to the communication device but uses a different signaling protocol than the first communication network. In order to notify the user of the waiting voicemail message in the voicemail server, a subscriber server (e.g., an HLR) in the first communication network receives a voicemail waiting indicator in the signaling protocol of the first communication network, identifies the signaling protocol of the second communication network, and converts the voicemail waiting indicator to the signaling protocol of the second communication network. The second communication network may then provide notification of the waiting voicemail message to the user.