Jochen Hasenmayer (born 28 October 1941 in Pforzheim, Germany)[1] is a German speleologist and cave diver from Birkenfeld in Baden-Württemberg, whose spectacular dives have frequently made headlines.

Hasenmayer began his cave diving career in 1957 at the age of fifteen, exploring the Falkensteiner Höhle near Stuttgart.

[2] Beginning in the 1960s, Hasenmayer explored many karst springs and caves in the Swabian Jura and elsewhere in Southern Germany, including the Wimsener Höhle, the Aachtopf and the Blautopf.

In the late 1970s, Hasenmayer was among the divers who searched for an underwater connection between Kingsdale Master Cave and Keld Head in the Yorkshire Dales.

Well known as a safety fanatic, Hasenmayer has introduced unique practices perceived by some cave divers as safe, but which contradict the basic rules of normal diving.

[8] Hasenmayer and American cave diver Sheck Exley became friends and rivals in the 1980s, each repeatedly attempting to break the depth records of the other.

[8][9][11] Due to a faulty depth gauge, in 1989 Hasenmayer surfaced too quickly after a dive in the Wolfgangsee, a lake in Austria.