Article 51 Vienna Convention on Diplomatic Relations
1.The present Convention shall enter into force on the thirtieth day following the date of deposit of the twenty-second instrument of ratification or accession with the Secretary-General of the United Nations.
2.For each State ratifying or acceding to the Convention after the deposit of the twenty-second instrument of ratification or accession, the Convention shall enter into force on the thirtieth day after deposit by such State of its instrument of ratification or accession.
See also: Article 50 Vienna Convention on Diplomatic Relations