The Hamburg U-Bahn is a rapid transit system serving the cities of Hamburg, Norderstedt, and Ahrensburg in Germany. Although referred to by the term U-Bahn, most of the system's track length is above ground. The network is interconnected with the city's S-Bahn system, which also has underground sections. It is operated by Hamburger Hochbahn within the Hamburger Verkehrsverbund (HVV). It was opened in February 1912, and comprises four lines serving 93 stations, with a route length of 106.4 kilometres (66.1 mi) in 2019.

The Hamburg S-Bahn is a rapid transit railway system in the Hamburg Metropolitan Region. Together, the S-Bahn, the Hamburg U-Bahn, the AKN railway and the regional railway form the backbone of railway public transport in the city and the surrounding area. The network has operated since 1907 as a commuter rail system, under the direction of the state railway, and is a member of the Hamburger Verkehrsverbund. There are four lines, serving 68 stations, on 147 kilometres (91 mi) of route. On an average working day the S-Bahn transports about 590,000 passengers; in 2010 about 221 million people used the S-Bahn.