| Country | Action | Action Date | Effective Date |
|---|
| Australia | Signature | 10/09/1919 | |
| Australia | Ratification | 16/07/1920 | |
| AUSTRIA | Signature | 10/09/1919 | |
| AUSTRIA | Ratification | 16/07/1920 | |
| BELGIUM | Signature | 10/09/1919 | |
| BELGIUM | Ratification | 24/07/1920 | |
| Canada | Signature | 10/09/1919 | |
| Canada | Ratification | 16/07/1920 | |
| CHINA | Signature | 10/09/1919 | |
| CHINA | Ratification | 16/07/1920 | |
| CUBA | Signature | 10/09/1919 | |
| CUBA | Ratification | 16/08/1920 | |
| CZECHOSLOVAKIA | Signature | 10/09/1919 | |
| CZECHOSLOVAKIA | Ratification | 16/07/1920 | |
| FRANCE | Signature | 10/09/1919 | |
| FRANCE | Ratification | 16/07/1920 | |
| GREECE | Signature | 10/09/1919 | |
| GREECE | Ratification | 16/07/1920 | |
| India | Signature | 10/09/1919 | |
| India | Ratification | 16/07/1920 | |
| ITALY | Signature | 10/09/1919 | |
| ITALY | Ratification | 16/07/1920 | |
| JAPAN | Signature | 10/09/1919 | |
| JAPAN | Ratification | 25/01/1921 | 14/10/1920 |
| New Zealand | Signature | 10/09/1919 | |
| New Zealand | Ratification | 16/07/1920 | |
| NICARAGUA | Signature | 10/09/1919 | |
| NICARAGUA | Ratification | 29/01/1921 | |
| PANAMA | Signature | 10/09/1919 | |
| POLAND | Signature | 10/09/1919 | |
| POLAND | Ratification | 22/08/1924 | |
| PORTUGAL | Signature | 10/09/1919 | |
| PORTUGAL | Ratification | 15/10/1921 | |
| ROMANIA | Accession | 09/12/1919 | |
| ROMANIA | Ratification | 04/09/1920 | |
| SERBIA | Accession | 05/12/1919 | |
| SERBIA | Ratification | 16/07/1920 | |
| SIAM | Signature | 10/09/1919 | |
| SIAM | Ratification | 16/07/1920 | |
| South Africa | Signature | 10/09/1919 | |
| South Africa | Ratification | 16/07/1920 | |
| UNITED KINGDOM | | | |
| UNITED STATES OF AMERICA | Signature | 10/09/1919 | |
| UNITED STATES OF AMERICA | Ratification | 16/07/1920 | |