Ditmar Koel, also Dithmar Koel, Ditmar Kohl or Dietmar Koehl (born around 1500, died 22 September 1563 in Hamburg), was a Captain, successful pirate hunter and Mayor of Hamburg.

7 October he came into sea battle with the fleet of the pirate Claus Kniphoff.

He brought the pirates and the loot to Hamburg, and was 1527 elected to Ratsherr (councilman).

In 1536, as Admiral for a defence fleet, he stopped a raid from Count Palatine Friedrich von Hadeln.

[1] In 1562 he traveled with two colleagues in a diplomatic journey to Copenhagen, in order to settle a conflict with the Danish king.