Slovakia:
1 January 1993 (Czechoslovakia split into the Czech
Republic and Slovakia)
Slovenia:
25 June 1991 (from Yugoslavia)
Solomon Islands:
7 July 1978 (from UK)
Somalia:
1 July 1960 (from a merger of British Somaliland, which
became independent from the UK on 26 June 1960, and Italian
Somaliland, which became independent from the Italian-administered
UN trusteeship on 1 July 1960, to form the Somali Republic)
South Africa:
31 May 1910 (from UK)
Spain:
1492 (expulsion of the Moors and unification)
Sri Lanka:
4 February 1948 (from UK)
Sudan:
1 January 1956 (from Egypt and UK)
Suriname:
25 November 1975 (from Netherlands)
Svalbard:
none (territory of Norway)