| Country | Action | Action Date | Effective Date |
|---|
| Australia | Extension | 26/07/1921 | |
| BELGIUM | Signature | 04/06/1920 | |
| BELGIUM | Ratification | 26/07/1921 | |
| Canada | Extension | 26/07/1921 | |
| CHINA | Signature | 04/06/1920 | |
| CHINA | Ratification | 01/10/1926 | |
| CUBA | Signature | 04/06/1920 | |
| CUBA | Ratification | 21/03/1922 | |
| CZECHOSLOVAKIA | Signature | 04/06/1920 | |
| CZECHOSLOVAKIA | Ratification | 26/07/1921 | |
| FRANCE | Signature | 04/06/1920 | |
| FRANCE | Ratification | 26/07/1921 | |
| GREECE | Signature | 04/06/1920 | |
| GREECE | Ratification | 15/10/1921 | |
| HUNGARY | Signature | 04/06/1920 | |
| HUNGARY | Ratification | 26/07/1921 | |
| India | Extension | 26/07/1921 | |
| ITALY | Signature | 04/06/1920 | |
| ITALY | Ratification | 26/07/1921 | |
| JAPAN | Signature | 04/06/1921 | |
| JAPAN | Ratification | 26/07/1921 | |
| New Zealand | Extension | 26/07/1921 | |
| NICARAGUA | Signature | 04/06/1920 | |
| PANAMA | Signature | 04/06/1920 | |
| POLAND | Signature | 04/06/1920 | |
| PORTUGAL | Signature | 04/06/1920 | |
| PORTUGAL | Ratification | 10/10/1923 | |
| ROUMANIA | Signature | 04/06/1920 | |
| ROUMANIA | Ratification | 26/07/1921 | |
| SERBIA | Signature | 04/06/1920 | |
| SERBIA | Ratification | 26/07/1921 | |
| SIAM | Signature | 04/06/1920 | |
| SIAM | Ratification | 26/07/1921 | |
| South Africa | Extension | 26/07/1921 | |
| UNITED KINGDOM | Signature | 04/06/1920 | |
| UNITED KINGDOM | Ratification | 26/07/1921 | |
| UNITED STATES OF AMERICA | Signature | 04/06/1920 | |