Erected on 28 June 1972 by Pope Paul VI; was established on the foundations of the Diocese of Kołobrzeg, which existed between 1000 and ca. 1015. The last territorial changes were introduced by Pope John Paul II on 24 February 2004. The capital of the diocese is Koszalin with the Cathedral of the Immaculate Conception of the Blessed Virgin Mary and the Co-Cathedral of the Assumption of the Blessed Virgin Mary in Kołobrzeg.