Idrottsföreningen Kamraterna Karlshamn were formed on 22 July 1906. In addition to football other sports in the early years included athletics, swimming, rowing, shooting, tennis and gymnastics. In the 1920s boxing, wrestling, handball, orienteering and bandy were added.
Football is now the main activity, the first match being played against a foreign team on 12 August 1907. IFK Karlshamn currently plays in Division 4 Blekinge which is the sixth tier of Swedish football. They play their home matches at the Vägga IP in Karlshamn.