The Holy See and Vatican City State have joined several international conventions (at times, with reservation). Among them are:

International Convention on the Elimination of All Forms of Racial Discrimination.

International Convention on the Rights of the Child

Single Convention on Narcotic Drugs and Amendment Protocol

Convention on Psychotropic Substances

Treaty on the Non-Proliferation of Nuclear Weapons

Outer Space Treaty

Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare

Geneva Conventions and their additional protocols (on improving conditions of the wounded and the sick during armed conflicts, on the protection of civilians, on the treatment of prisoners, on the statute of refugees).

International Convention for the Protection of Cultural Property in the Event of Armed Conflict

UNESCO Convention Concerning the Protection of the World Cultural and Natural Heritage

Vienna Convention on International Relations

European Cultural Convention

Convention on Law of the Sea

Convention on Road Traffic

Accession of the Holy See, in the name and on  behalf of Vatican City State, to the United Nations Convention Against Corruption (23 September 2016)

Accession of the Holy See, in the name and on behalf of Vatican City State, to the Convention of the Council of Europe on the Transfer of Sentenced Persons and to its additional protocols, (12 April 2019)

Accession of the Holy See to the Climate Convention and the Paris Agreement (8 July 2022)