| Contracting Parties/Signatories | Signature | Instrument | In Force | Details |
|---|
| Albania | April 20, 1921 | Ratification: October 8, 1921 | October 31, 1922 | |
| Antigua and Barbuda | | Declaration / Notification of Succession: October 25, 1988 | November 1, 1981 | |
| Austria | April 20, 1921 | Ratification: November 15, 1923 | February 13, 1924 | |
| Belgium | April 20, 1921 | Ratification: May 16, 1927 | August 14, 1927 | |
| Bolivia (Plurinational State of) | April 20, 1921 | | | |
| Bosnia and Herzegovina | | Declaration / Notification of Succession: September 1, 1993 | March 6, 1992 | |
| Bulgaria | April 20, 1921 | Ratification: June 11, 1922 | October 31, 1922 | |
| Cambodia | | Declaration / Notification of Succession: April 12, 1971 | November 9, 1953 | |
| Chile | April 20, 1921 | Ratification: March 19, 1928 | June 17, 1928 | |
| China | April 20, 1921 | | | Details |
| Croatia | | Declaration / Notification of Succession: August 3, 1992 | October 8, 1991 | |
| Czech Republic | | Declaration / Notification of Succession: February 9, 1996 | January 1, 1993 | |
| Denmark | April 20, 1921 | Ratification: November 13, 1922 | February 11, 1923 | |
| Estonia | April 20, 1921 | Ratification: June 6, 1925 | September 4, 1925 | |
| Fiji | | Declaration / Notification of Succession: March 15, 1972 | October 10, 1970 | |
| Finland | April 20, 1921 | Ratification: January 29, 1923 | April 29, 1923 | |
| France | April 20, 1921 | Ratification: September 19, 1924 | December 18, 1924 | |
| Georgia | | Accession: June 2, 1999 | August 31, 1999 | |
| Germany | | Accession: April 9, 1924 | July 7, 1924 | |
| Greece | April 20, 1921 | Ratification: February 18, 1924 | May 18, 1924 | |
| Guatemala | April 20, 1921 | | | |
| Hungary | | Accession: May 18, 1928 | August 16, 1928 | |
| India | April 20, 1921 | Ratification: August 2, 1922 | October 31, 1922 | |
| Iran (Islamic Republic of) | April 20, 1921 | Ratification: January 29, 1931 | April 29, 1931 | |
| Iraq | | Accession: March 1, 1930 | May 30, 1930 | |
| Italy | April 20, 1921 | Ratification: August 5, 1922 | November 3, 1922 | |
| Japan | April 20, 1921 | Ratification: February 20, 1924 | May 20, 1924 | |
| Lao People's Democratic Republic | | Declaration / Notification of Succession: November 24, 1956 | October 22, 1953 | |
| Latvia | April 20, 1921 | Ratification: September 29, 1923 | December 28, 1923 | |
| Lebanon | | Accession: February 7, 1929 | May 8, 1929 | |
| Lesotho | | Declaration / Notification of Succession: October 23, 1973 | October 4, 1966 | |
| Liberia | | Accession: September 16, 2005 | December 15, 2005 | |
| Lithuania | April 20, 1921 | | | |
| Luxembourg | April 20, 1921 | Ratification: March 19, 1930 | June 17, 1930 | |
| Malawi | | | | Details |
| Malta | | Declaration / Notification of Succession: May 13, 1966 | September 21, 1964 | |
| Mauritius | | Declaration / Notification of Succession: July 18, 1969 | March 12, 1968 | |
| Nepal | | Accession: August 22, 1966 | November 20, 1966 | |
| Netherlands | April 20, 1921 | Ratification: April 17, 1924 | July 16, 1924 | Details |
| New Zealand | April 20, 1921 | Ratification: August 2, 1922 | October 31, 1922 | |
| Nigeria | | Accession: November 3, 1967 | February 1, 1968 | |
| Norway | April 20, 1921 | Ratification: September 4, 1923 | December 3, 1923 | |
| Panama | April 20, 1921 | | | |
| Poland | April 20, 1921 | Ratification: October 8, 1924 | January 6, 1925 | |
| Portugal | April 20, 1921 | | | |
| Romania | April 20, 1921 | Ratification: September 5, 1923 | December 4, 1923 | |
| Rwanda | | Declaration / Notification of Succession: February 10, 1965 | July 1, 1962 | |
| Saint Vincent and the Grenadines | | Declaration / Notification of Succession: September 5, 2001 | October 27, 1979 | |
| Serbia | | Ratification: May 7, 1930 | August 5, 1930 | |
| Slovakia | | Declaration / Notification of Succession: May 28, 1993 | January 1, 1993 | |
| Slovenia | | Declaration / Notification of Succession: July 6, 1992 | June 25, 1991 | |
| Spain | April 20, 1921 | Ratification: December 17, 1929 | March 17, 1930 | |
| Swaziland | | Accession: November 24, 1969 | February 22, 1970 | |
| Sweden | April 20, 1921 | Ratification: January 19, 1925 | April 19, 1925 | |
| Switzerland | April 20, 1921 | Ratification: July 14, 1924 | October 12, 1924 | |
| Syrian Arab Republic | | Accession: February 7, 1929 | May 8, 1929 | |
| Thailand | | Accession: November 29, 1922 | February 27, 1923 | |
| Turkey | | Ratification: June 27, 1933 | September 25, 1933 | |
| United Kingdom | April 20, 1921 | Ratification: August 2, 1922 | October 31, 1922 | Details |
| Uruguay | April 20, 1921 | | | |
| Zimbabwe | | Declaration / Notification of Succession: December 1, 1998 | April 18, 1980 | |
