The primary distinction in becoming a Party is usually made between ratification and accession. Only those States that signed the Protocol when it was open for signature (i.e. between its adoption and the closing date for signature 4 June 2001) can proceed to ratify it. In signing the Protocol, States only indicated general support for its objective and provisions as well as their intention to become Parties in the future and be legally bound by it. However, the act of signing, in itself, did not establish consent to be bound by the Protocol. Therefore, the further act of ratification is required before the State becomes a Party.

The instrument of ratification is signed by the Head of State, Government or Minister for Foreign Affairs and deposited with the Depositary – the Secretary-General of the United Nations. Once a State has deposited this instrument, the Protocol then enters into force for that State ninety days later. At this point, the State is bound by the provisions of the Protocol and must comply with its obligations.

States that did not sign the Protocol during the time when it was open for signature cannot ratify it – they may only accede to it. These States therefore deposit an instrument of accession in order to become a Party. (Note: These States have the same rights and obligations as those States that ratified the Protocol.)