Baltic Sea States Subregional Co-operation (BSSSC) was established in 1993, based on the Stavanger Declaration, and as a result of the establishment of the Council of Baltic Sea States (CBSS) in 1992.

BSSSC' participants are regional authorities (level directly below the national level authorities) of the 10 Baltic Sea littoral states: Germany, Denmark, Finland, Sweden, Norway, Poland, Latvia, Lithuania, Estonia and Russia.