The Alsterschwimmhalle is like most German public swimming pools: underfunded, dated, rather…read morescruffy and, generally speaking, not the cosiest place to spend time in. But there is some silver lining to that grey cloud - in the shape of the city's longest swimming lanes, as well as very generous opening hours. That means if your goal isn't relaxation or fun, but the sport aspect of swimming you might find what you're looking for at Alsterschwimmhalle rather than some of the more modern water parks.
Just one final piece of advice: avoid visiting in the evenings, for the water and the changing rooms tend not to be in the cleanliest of states after a hard day's abuse.
Fans of late sixties/early seventies architecture should also get a kick out of the avantgarde concrete roof structure and overlook the half-hearted renovation attempts the building is littered with.