| Country | Action | Action Date | Effective Date |
|---|
| ANGOLA | Accession | 27/09/2007 | 27/12/2007 |
| AUSTRIA | Accession | 01/01/1909 | |
| BELGIUM | Signature | 20/03/1883 | |
| BELGIUM | Ratification | 06/06/1884 | |
| BRAZIL | Signature | 20/03/1883 | |
| BRAZIL | Ratification | 06/06/1884 | |
| BRUNEI DARUSSALAM | Accession | 17/11/2011 | 17/02/2012 |
| DENMARK | Membership | 01/10/1894 | |
| DOMINICAN REPUBLIC | Accession | 08/12/1884 | |
| FRANCE | Signature | 20/03/1883 | |
| FRANCE | Ratification | 06/06/1884 | |
| Gibraltar | Extension | 01/10/2020 | 01/01/2021 |
| GUATEMALA | Signature | 20/03/1883 | |
| GUATEMALA | Ratification | 06/06/1884 | |
| GUATEMALA | Withdrawal | 08/11/1894 | |
| Guernsey, Bailiwick of | Extension | 13/08/2020 | 13/11/2020 |
| HUNGARY | Accession | 01/01/1909 | |
| Isle of Man | Extension | 27/07/1983 | 29/10/1983 |
| ITALY | Signature | 20/03/1883 | |
| ITALY | Ratification | 06/06/1884 | |
| JAPAN | Accession | 04/05/1899 | |
| JAPAN | Accession | 01/01/1905 | |
| Jersey, Bailiwick of | Extension | 13/08/2020 | 13/11/2020 |
| NETHERLANDS THE | Signature | 20/03/1883 | |
| NETHERLANDS THE | Ratification | 06/06/1884 | |
| New Zealand | Accession | 29/08/1891 | |
| PORTUGAL | Signature | 20/03/1883 | |
| PORTUGAL | Ratification | 06/06/1884 | |
| SALVADOR | Signature | 20/03/1883 | |
| SALVADOR | Ratification | 06/06/1884 | |
| SALVADOR | Withdrawal | 06/09/1886 | |
| SERBIA | Signature | 20/03/1883 | |
| SERBIA | Ratification | 06/06/1884 | |
| SERBIA | Accession | 10/10/1909 | |
| SERBIA | Declaration | 19/09/2006 | |
| SPAIN | Signature | 20/03/1883 | |
| SPAIN | Ratification | 06/06/1884 | |
| SWEDEN AND NORWAY | Accession | 18/06/1885 | |
| SWITZERLAND | Signature | 20/03/1883 | |
| SWITZERLAND | Ratification | 06/06/1884 | |
| TRINIDAD AND TOBAGO | Accession | 14/05/1908 | |
| UNITED KINGDOM | Accession | 17/03/1884 | |