Stephane Sessegnon registered his second goal of the tour after scoring in the 1-1 draw against Arminia Bielefeld at the weekend, with around 300 Sunderland fans making the trip to the Weserbergland-Stadion in Hamelin.
Prior to last night's match, Hannover had scored 59 goals in just five pre-season fixtures, and that hot streak showed no sign of ending in Hamelin when Mohammed Abdellaoue opened the scoring.
Sunderland went in 2-0 down at the interval when Jan Schlaudraff added to Hannover's lead three minutes after the first goal.
Manager Steve Bruce made four changes during the match as his players gain in match fitness.
Louis Laing continued his good form with a start in the centre of defence alongside Anton Ferdinand, while Ji Dong-Won continued his own game of catch-up with a decent stint up top alongside Sessegnon.
Hannover fielded former Middlesbrough defender Emanuel Pogatetz and rarely looked like being bettered despite Sessegnon's second half finish.
They restored their two-goal advantage, despite some Sunderland pressure, with a cool volley by Erdal Akdari to complete a 3-1 win.
Asamoah Gyan watched from the stands and will make his first appearance of pre-season when the Black Cats return from Germany.
Next up, though, is a trip to Borussia Monchengladbach on Saturday.
Sunderland: Mignolet, Bardsley (Larsson), Richardson, Ferdinand, Laing, Elmohamady, Vaughan, Colback, Gardner (Cattermole), Sessegnon (Wickham), Dong-won (Malbranque). Subs not used: Pickford, Tounkara.