| 27 November 1849 |
20 February 1850 |
Treaty of Friendship, Commerce, and Navigation between Great Britain and Costa Rica |
| 27 September 1887 |
15 December 1887 |
Convention with the Postal Administration of the Republic of Costa Rica for the exchange of postal parcels, with Detailed Regulations |
| 26 April 1907 |
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Agreement between the United Kingdom and the Republic of Costa Rica for the Exchange of Postal Money Orders |
| 23 May 1921 |
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Exchange of Notes between Great Britain and Costa Rica relative to the Importation from Great Britain into Costa Rica of Opium and similar Drugs |
| 12 January 1922 |
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Convention between Her Majesty's Government and the Government of Costa Rica for the Submission to Arbitration of Certain Claims against the Government of Costa Rica |
| 27 December 1928 |
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Convention between His Majesty's Government in the United Kingdom and the Government of Costa Rica respecting Commercial Travellers |
| 2 August 1933 |
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Exchange of Notes between the Government of the Irish Free State and the Costa Rican Government in regard to Commercial Relations |
| 18 November 1950 |
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Agreement between Canada and Costa Rica |
| 12 November 1968 |
19 December 1968 |
Exchange of Notes between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the Republic of Costa Rica concerning the Abolition of Visas |
| 25 June 1975 |
12 August 1976 |
Exchange of Notes between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the Republic of Costa Rica further amending the United Kingdom / Costa Rica Loan 1973 |