Treaty on the Prohibition of the Emplacement of Nuclear Weapons and Other Weapons of Mass Destruction on the Seabed and Ocean Floor and in the Subsoil Thereof (Seabed Treaty)

Note: As of February 2008, this page will no longer be updated.


  • Opened for Signature: 11 February 1971
  • Entered into Force: 18 May 1972
  • Number of Parties: 95 States
  • Number of Signatories: 21 States
  • Depositories: Russia (originally the Soviet Union), United Kingdom, and United States


In the 1960s, there were concerns that due to recent advances in oceanographic technologies, nations might use the seabed as a new environment for nuclear-related military installations. The Soviet Union and the United States submitted two separate drafts that differed on what was to be prohibited and verification measures. On 7 October 1969, the two States submitted a joint draft to the Conference of the Committee on Disarmament (CCD). During the deliberations in the CCD, coastal States raised concerns about the protection of their rights and smaller States had doubts whether they could check on violations. The final draft was approved by the United Nations General Assembly's Resolution 2660 (XXV) on 7 December 1970 by a vote of 104 to 2 (El Salvador, Peru), with two abstentions (Ecuador, France). The Seabed Treaty was opened for signature on 11 February 1971 and entered into force on 18 May 1972, when the Soviet Union, the United States, and the United Kingdom, as well as more that 22 nations had deposited instruments of ratification.

Treaty Obligations

The Treaty forbids States Parties from implanting or placing on the seabed or ocean floor or in the subsoil thereof, beyond a 12-mile territorial zone, any nuclear weapons or any other types of weapons of mass destruction or structures, launching installations, or any other facilities specifically designed for storing, testing, or using such weapons.

Verification and Compliance


The Treaty allows for verification through observation by the States Parties of the activities of other States Parties, provided that observation does not interfere with such activities. If after such observation reasonable doubts remain, further procedures for verification may be agreed upon, including inspections. After completion of the further procedures for verification, an appropriate report shall be circulated to other Parties by the Party that initiated such procedures.


If consultation and cooperation have not removed the doubts concerning the activities and there remains a serious question concerning fulfillment of the obligations assumed under this Treaty, a State Party may, in accordance with the provisions of the Charter of the United Nations, refer the matter to the Security Council, which may take action in accordance with the Charter.

Review Conferences

As set forth in Article VII of the Treaty, review conferences have been held every five years in 1977, 1983, and 1989. In 1989, it was agreed that the next review conference would be held no sooner than 1996. In 1992, the Conference on Disarmament informally considered further measures and established no need for a fourth review conference.


The treaty prevents placement of NBC weapons on the seabed and ocean floor to eliminate the possibility of an underwater arms race and promote the peaceful exploration of water bodies.

This material is produced independently for NTI by the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, or agents. Copyright 2019.