Eckernförde Naval Base (Kranzfelder-Hafen)

Eckernförde Naval Base, whose harbour is named Kranzfelder-Hafen after Alfred Kranzfelder, is a German Navy installation on the Baltic coast at Eckernförde in Schleswig-Holstein, in the Louisenberg district of the town. It is the German Navy's only deep-water harbour on the Baltic, with depths reaching 17.5 metres at the eastern outer mole. The base is administered by Marinestützpunktkommando Eckernförde and falls under the Marinestützpunktkommando Kiel.

The base is the home port of the German submarine force. It hosts the 1. Ubootgeschwader (1st Submarine Squadron) and the submarine training centre, Ausbildungszentrum Uboote. Homeported units comprise the Type 212A submarines, the Oste-class intelligence collection ships (Flottendienstboote) and the Elbe-class tender Main. The multi-purpose boat Stollergrund and the training boat Langeoog are also based there.

Eckernförde is the seat of the German Navy's ground and special operations elements: the Seebataillon and the Kommando Spezialkräfte der Marine (KSM), the naval special forces command. Other resident commands include the Marineunterstützungskommando (formerly the command for naval troop trials), the Zentrum Einsatzprüfung, the navy's hydroacoustic analysis centre, the Maritimes Unterstützungszentrum, a rapid-repair section of the Marineamt's naval armament and logistics branch, a medical support centre and a Bundeswehr fire brigade.

The base area is divided in two. The western part belongs to the Wehrtechnische Dienststelle 71 (WTD 71), the technical centre for ships, naval weapons, maritime technology and research, with its trials vessels berthed in the adjoining harbour section; the research ship Planet of Class 751 is assigned there. WTD 71 also operates the Centre for Naval Mine Warfare and a section for underwater detonics, weapons effects and firing and explosives trials. The eastern part comprises the naval base proper. A diver training hall, returned to service in 2024 after refurbishment, supports indoor training of mine clearance divers and combat swimmers.

An outstation of the Kiel naval base command existed at Eckernförde from 1 April 1957. It was raised to an independent naval base on 1 July 1985. From 1 October 1994 to 1 October 2001 it was subordinated to Marineabschnittskommando Nord, after which control passed back to Marinestützpunktkommando Kiel.