| Country | Action | Action Date | Effective Date |
|---|---|---|---|
| ALBANIA | Signature | 20/04/1921 | |
| ALBANIA | Ratification | 18/10/1921 | |
| ANTIGUA AND BARBUDA | Succession | 25/10/1988 | 01/11/1981 |
| Antilles | Extension | 01/01/1986 | |
| Aruba | Extension | 01/01/1986 | |
| AUSTRIA | Signature | 20/04/1921 | |
| AUSTRIA | Ratification | 15/11/1923 | |
| BELGIUM | Signature | 20/04/1921 | |
| BELGIUM | Ratification | 16/05/1927 | |
| BOLIVIA | Signature | 20/04/1921 | |
| BOSNIA AND HERZEGOVINA | Succession | 01/09/1993 | 06/03/1992 |
| BRITISH EMPIRE | Signature | 20/04/1921 | |
| BRITISH EMPIRE | Declaration | 20/04/1921 | |
| BRITISH EMPIRE | Ratification | 02/08/1922 | |
| BULGARIA | Signature | 20/04/1921 | |
| BULGARIA | Ratification | 11/07/1922 | |
| CHILE | Signature | 20/04/1921 | |
| CHILE | Ratification | 19/03/1928 | |
| CHINA | Signature | 20/04/1921 | |
| CROATIA | Succession | 03/08/1992 | 08/10/1991 |
| CZECH REPUBLIC | Succession | 09/02/1996 | 01/01/1993 |
| CZECHOSLOVAKIA | Signature | 20/04/1921 | |
| CZECHOSLOVAKIA | Ratification | 29/10/1923 | |
| DANZIG | Accession | 03/04/1925 | |
| DENMARK | Signature | 20/04/1921 | |
| DENMARK | Ratification | 13/11/1922 | |
| ESTONIA | Signature | 20/04/1921 | |
| ESTONIA | Ratification | 06/06/1925 | |
| FIJI | Succession | 15/03/1972 | |
| FINLAND | Signature | 20/04/1921 | |
| FINLAND | Ratification | 29/01/1923 | |
| FRANCE | Signature | 20/04/1921 | |
| FRANCE | Ratification | 19/09/1924 | |
| GEORGIA | Accession | 02/06/1999 | 31/08/1999 |
| GERMANY | Accession | 09/04/1924 | |
| GREECE | Signature | 20/04/1921 | |
| GREECE | Ratification | 18/02/1924 | |
| GUATEMALA | Signature | 20/04/1921 | |
| Hong Kong | Withdrawal | 01/07/1997 | |
| HONG KONG SAR | Application | 06/06/1997 | 01/07/1997 |
| HUNGARY | Accession | 18/05/1928 | |
| INDIA | Signature | 20/04/1921 | |
| INDIA | Ratification | 02/08/1922 | |
| IRAQ | Accession | 01/03/1930 | |
| ITALY | Signature | 20/04/1921 | |
| ITALY | Ratification | 05/08/1922 | |
| JAPAN | Signature | 20/04/1921 | |
| JAPAN | Ratification | 20/02/1924 | |
| KHMER REPUBLIC | Succession | 12/04/1971 | |
| LAOS | Accession | 24/11/1956 | |
| LATVIA | Signature | 20/04/1921 | |
| LATVIA | Ratification | 29/09/1923 | |
| LESOTHO | Succession | 23/10/1973 | |
| LIBERIA | Accession | 16/09/2005 | 15/12/2005 |
| LITHUANIA | Signature | 20/04/1921 | |
| LUXEMBOURG | Signature | 20/04/1921 | |
| LUXEMBOURG | Ratification | 19/03/1930 | |
| MALAWI | Withdrawal | 03/09/1968 | |
| Malay States, Federated | Accession | 02/09/1923 | |
| Malay States, Unfederated | Accession | 02/09/1923 | |
| MALTA | Succession | 13/05/1966 | 21/09/1964 |
| MAURITIUS | Succession | 12/03/1968 | |
| NEPAL | Accession | 22/08/1966 | |
| NETHERLANDS THE | Signature | 20/04/1921 | |
| NETHERLANDS THE | Ratification | 17/04/1924 | |
| NEW ZEALAND | Signature | 20/04/1921 | |
| NEW ZEALAND | Ratification | 02/08/1922 | |
| NIGERIA | Accession | 03/11/1967 | |
| NORWAY | Signature | 20/04/1921 | |
| NORWAY | Ratification | 04/09/1923 | |
| Palestine | Accession | 28/01/1924 | |
| PANAMA | Signature | 20/04/1921 | |
| PERSIA | Signature | 20/04/1921 | |
| PERSIA | Ratification | 29/01/1931 | |
| POLAND | Signature | 20/04/1921 | |
| POLAND | Ratification | 08/10/1924 | |
| PORTUGAL | Signature | 20/04/1921 | |
| ROUMANIA | Signature | 20/04/1921 | |
| ROUMANIA | Ratification | 05/09/1923 | |
| RWANDA | Accession | 10/02/1965 | |
| SERB-CROAT-SLOVENE STATE | Signature | 20/04/1921 | |
| SIAM | Accession | 29/11/1922 | |
| SLOVAK REPUBLIC | Succession | 28/05/1993 | 01/01/1993 |
| SLOVENIA | Succession | 01/07/1992 | 25/06/1991 |
| SPAIN | Signature | 20/04/1921 | |
| SPAIN | Ratification | 17/12/1929 | |
| ST VINCENT AND THE GRENADINES | Succession | 05/09/2001 | 27/10/1979 |
| SWAZILAND | Succession | 24/11/1969 | 22/02/1970 |
| SWEDEN | Signature | 20/04/1921 | |
| SWEDEN | Ratification | 19/01/1925 | |
| SWITZERLAND | Signature | 20/04/1921 | |
| SWITZERLAND | Ratification | 14/07/1924 | |
| SYRIA & GRAND LEBANON | Accession | 07/02/1929 | |
| TURKEY | Accession | 27/06/1933 | |
| UNITED KINGDOM | Signature | 20/04/1921 | |
| UNITED KINGDOM | Ratification | 02/08/1922 | |
| URUGUAY | Signature | 20/04/1921 | |
| YUGOSLAVIA | Ratification | 07/05/1930 | |
| ZIMBABWE | Succession | 01/12/1998 | 18/04/1980 |