The small cruisers of the Kolberg class were significant bigger than their predecessor, enabling to add two additional 10,5 cm guns to the ships. All four ships had different kind of turbines to find the best of them for later cruiser designs: Melms & Pfenninger (Kolberg ), Parsons (Augsburg ), Schneider-Zoelly (Cöln ) and AEG-Curtis (Mainz ). Those installed in the Cöln proofed to be very unreliable therefore they were exchanged with Germania-turbines after trials.

Like many other small cruisers, their main armament was replaced during the war, the twelve 10,5 cm guns were replaced with six 15 cm guns. They were good seagoing ships, but had a bad maneuverability.

Cöln and Mainz were both sunk in the Battle of Helgoland where the German reconnaissance forces were attacked by British battlecruisers. Cöln was flagship of the torpedo boats and attacked the British cruiser Fearless in this battle until it was heavily shelled and sunk by the British battlecruisers Lion and Princes Royal , with all but one of the crew lost. In August of 1979 the wreck was moved to a nearby location at the bottom of the North Sea.