Acceptance/ Approval

The act whereby a State indicates its consent to become a party to a treaty. Acceptance/Approval are specifically provided for in a treaty and can take the form of a letter or a standard format prescribed by the treaty itself.


The act whereby a State that has not signed a treaty expresses its consent to become a party by depositing an Instrument of Accession. Accession has the same legal effect as Ratification.


The formal act by which negotiating parties establish the form and content of a treaty. The treaty is adopted through a specific act expressing the will of the States by voting on the text, initialling, signing, etc.

Consent to be bound

A State expresses its consent to be bound by a treaty under international law by some formal act, i.e. definitive signature, ratification, acceptance, approval or accession.


Credentials is a document issued by a State authorising a delegate or delegation of that State to attend a conference, including where necessary, for the purpose of negotiating and adopting the text of a treaty.


The depositary of a treaty is the custodian of the treaty and is entrusted with the functions specified in article 77 of the Vienna Convention 1969.


Entry into



The moment in time when a treaty becomes legally binding on the parties to a treaty.

Exchange of Notes

May embody a bilateral treaty commitment. The signatures of both parties appear on two separate Notes. The agreement lies in the exchange of these Notes, each of the parties retaining one Note signed by the representative of the other party. In a bilateral treaty the parties may also exchange Notes to indicate that they have completed all domestic procedures necessary to implement the treaty.



The act undertaken on the international plane, whereby a State that has signed the treaty confirm its consent to be bound by a treaty. This is done by depositing an Instrument of Ratification with the depositary. This should not be confused with the act of ratification at a national level which a State may be required to undertake in accordance with its own constitutional provisions.


Article 2(1) (d) of the Vienna Convention on the Law of Treaties defines a reservation as: “A unilateral statement, however phrased or named, made by a State, when signing, ratifying, accepting, approving or acceding to a treaty, whereby it purports to exclude or to modify the legal effect of certain provisions of the treaty in their application to the State.”