o2 Voicemail is a voicemail solution for Android offered by Telefónica Germany GmbH & Co. OHG. It is designed to replace the old voicemail system with a newer platform that provides an improved Visual Voicemail function. The new platform requires users to install the o2 Voicemail app in order to continue using the service.

Once the app is installed and the mobile phone is logged into the o2 network, it automatically registers with Voicemail. This allows mailbox messages to be loaded into the memory of the user's own mobile phone. When a call is missed, the called subscriber is informed on the display. The start screen of the mobile phone shows the number of existing messages.

The o2 Voicemail app offers extended mailbox functionalities, allowing users to listen to and manage messages, call back contacts, send SMS, and manage, activate, and record greetings. It is important to note that in order for the app to work properly, the energy-saving mode for the app needs to be deactivated. Failure to do so may result in new messages being displayed with significant delay.

Please note that the o2 Voicemail app is currently only available for o2 contract customers. o2 prepaid and third-party providers are not supported at the moment.