In 1972 he prepared a memorandum to the UN on behalf of two underground citizens' groups, which asked for the UN assistance to evacuate the Soviet occupation forces and organize free elections.

He stayed for the next dozen years under strict KGB surveillance but continued to operate half-underground, organizing unofficial opposition groups and passing to the West information about human rights violations in the Soviet occupied Estonia.

In August 1991 he was instrumental in achieving a national understanding with the Soviet Estonia's Supreme Council on the principles of restoring Estonian statehood.

He is also a board member of the Human Rights Institute (since 1997), the Kistler-Ritso Foundation (since 1998) which built the Museum of Occupations in Tallinn and was chief elder of the Estonian Scouting Association (1996–2007).

He also initiated the publication of the book "Reunification of Europe" (2009) which presents the 20th century experiences of ten post-Communist EU member states.

Tunne Kelam has been decorated with the Estonian Order of the Coat of Arms, 1st class (2005), with the French Grand Officier de l'Ordre National du Merité (2001), with Robert Schuman medal and honorary diploma (2006), with the Baltic Parliamentary Assembly's Diploma and the Sash of Honour for the outstanding contribution to the restoration of independence (1999), with Rotary International Paul Harris award (1990) etc.