She sailed from Eckernförde on 22 January 2009, bound for the Mediterranean to participate in the anti-terrorism mission Operation Active Endeavour.

During this time she trialled the multi-crew concept, with three crews taking turns manning the submarine until her return to port on 11 December 2011.

[7] In September she took part in multinational CASEX exercises in the Baltic, with surface ships of the German, Polish and Swedish navies.

[8] In October U-34 took part in Grüner Aal (Green Eel) manoeuvres, a series of torpedo training exercises with the Royal Norwegian Navy.

[9] On 30 March 2016 U-34 deployed from Eckernförde to the coast of Scotland, joining Standing NATO Maritime Group 1 and taking part in Exercise Joint Warrior, returning to her homeport in May.