The Type 423 Oste class are purpose built signals intelligence (SIGINT/ELINT) and reconnaissance ships of the German Navy.

[1] Officially designated as "fleet service ships", they replaced the Type 422 class.

The Oste-class ships were designed as reconnaissance units during the Cold War.

From the 1990s, the tasks were expanded to early warning and telecommunications reconnaissance in cooperation with other units of German and international armed forces.

[3] Later she was seen in Greenwich, UK in February 2017[4] In June 2021, the Bundestag approved the development and procurement of three fleet service boats as well as a training and reference reconnaissance facility (ARAA) for sea-based signal detection reconnaissance (ssA).