Beitrittsinstrument

Beitrittsinstrument is the formal written instrument by which a state or international organization becomes a party to a treaty through accession. In international law, accession is the act of joining a treaty after its adoption and signature by other states. The Beitrittsinstrument is typically signed by the appropriate authority of the acceding state and deposited with the treaty’s depositary, such as a designated international organization or the Secretary-General of the United Nations.

Upon deposition and the fulfillment of any internal ratification or approval requirements, the acceding state becomes bound by the treaty. The consent to be bound may take effect on a date specified in the instrument, on the date the treaty enters into force for that state, or on another date provided in the treaty. The instrument thus has the same legal effect as other forms of consent to be bound, such as ratification or acceptance, depending on the treaty’s terms.

Depositaries maintain a public register of parties, and the entry into force for the acceding state follows the treaty’s rules on entry into force for new parties. Accession is commonly used by states that did not participate in the treaty’s negotiation but wish to become party later. It should be distinguished from signature, which is typically a preliminary step, and from ratification or approval, which are other procedural steps taken by a negotiating state.