| 2 May 1952 |
|
Exchange of Notes between the United Kingdom and Tonga amending Article 5 of the Treaty of Friendship of 18.05.1900 |
| 26 August 1958 |
25 May 1959 |
Treaty of Friendship between Her Majesty the Queen in respect of the United Kingdom of Great Britain and Northern Ireland and Her Majesty the Queen of Tonga |
| 23 June 1964 |
16 July 1964 |
Exchange of Notes between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the Kingdom of Tonga amending the Treaty of Friendship signed on August 26, 1958 |