| Name | Issues/Designs | |||
| Tenth February Society, Oruro founding | 1887 | — | - 100th Anniversary of the ... | |
| Treaty of Rome start | 1957 | — | - 50th Anniversary of the ... | |
| Trinidad, Bolivia opening | 1686 | — | - 300th Anniversary of ... | |
| UNICEF founding | 1946 | — | - 50th Anniversary of ... syns. United Nations International Children's Emergency Fund founding | |
| UN founding | 1945 | — | (3) - UN 5th, 40th Anniversary of the ..., 50th Anniversary of the ... | |
| Universal Postal Union founding | 1874 | — | syns. UPU founding, U.P.U. founding | |
| Uyuni opening | 1889 | — | - 100th Anniversary of ... | |
| Yacuma Province - Beni Department opening | 1895 | — | - 100th Anniversary of the ... | |
| YPFB Corporation founding | 1936 | — | - 75th Anniversary of ... |