Bureau of International Security and Nonproliferation

Signed at Washington, London, and Moscow February 11, 1971
Entered into force May 18, 1972

Treaty Text
Signatory List


Like the Antarctic Treaty, the Outer Space Treaty, and the Latin American Nuclear-Free Zone, the Seabed Treaty sought to prevent the introduction of international conflict and nuclear weapons into an area hitherto free of them. Reaching agreement on the seabed, however, involved problems not met in framing the other two agreements.

In the 1960s, advances in the technology of oceanography and greatly increased interest in the vast and virtually untapped resources of the ocean floor led to concern that the absence of clearly established rules of law might lead to strife. And there were concurrent fears that nations might use the seabed as a new environment for military installations, including those capable of launching nuclear weapons.

In keeping with a proposal submitted to the U.N. Secretary General by Ambassador Pardo of Malta in August 1967, the U.N. General Assembly, on December 18, 1967, established an ad hoc committee to study ways of reserving the seabed for peaceful purposes, with the objective of ensuring "that the exploration and use of the seabed and the ocean floor should be conducted in accordance with the principles and purposes of the Charter of the United Nations, in the interests of maintaining international peace and security and for the benefit of all mankind." The Committee was given permanent status the following year. At the same time, seabed-related military and arms control issues were referred to the ENDC and its successor, the CCD.1 In a message of March 18, 1969, President Nixon said the American delegation to the ENDC should seek discussion of the factors necessary for an international agreement prohibiting the emplacement of weapons of mass destruction on the seabed and ocean floor and pointed out that an agreement of this kind would, like the Antarctic and Outer Space treaties, "prevent an arms race before it has a chance to start."

On March 18, 1969, the Soviet Union presented a draft Treaty that provided for the complete demilitarization of the seabed beyond a 12-mile limit and making all seabed installations open to Treaty parties on the basis of reciprocity. The U.S. draft Treaty, submitted on May 22, prohibited the emplacement of nuclear weapons and other weapons of mass destruction on the seabed and ocean floor beyond a three-mile band. This, the United States held, was the urgent problem, and complete demilitarization would not be verifiable.

As can be seen, the two drafts differed importantly on what was to be prohibited. The Soviet draft would have banned all military uses of the seabed. It would have precluded, for example, submarine surveillance systems that were fixed to the ocean floor. The United States regarded these as essential to its defense.

The two drafts also differed on the issue of verification. Using as a model the provisions for verification in the Outer Space Treaty, the Soviets proposed that all installations and structures be open to inspection, provided that reciprocal rights to inspect were granted. The United States contended that on the Moon no claims of national jurisdiction existed and that provisions suitable for the Moon would not be adequate for the seabed, where many claims of national jurisdiction already existed and many kinds of activities were in progress or possible. Moreover, the United States felt that to attempt to inspect for the emplacement of all kinds of weapons would make the problems connected with verification virtually insuperable.

On the other hand, the United States stated the case that any structures capable of handling nuclear devices would necessarily be large and elaborate; their installation would require extensive activity, difficult to conceal; and there would probably be a number of devices involved, as it would not be worth violating the Treaty simply to install one or two weapons. Violations, therefore, would be readily observed and evoke the appropriate steps -- first an effort to deal directly with the problem through consultations with the country violating the Treaty; if that failed, recourse to cooperative action; and, as a last resort, appeal to the Security Council.

Comments on the two drafts in the ENDC, U.S. consultations with its NATO allies, and private U.S.-Soviet talks at the ENDC eventually led to the framing of a joint draft by the United States and the Soviet Union, submitted on October 7, 1969, to the CCD. This joint draft underwent intensive discussion and was three times revised in response to suggestions made in the CCD and at the United Nations.

Discussion centered on a few difficult issues. In international law there was much confusion about how territorial waters were to be defined. Some countries claimed up to 200 miles, and international conventions on the subject contained ambiguities. In its final form the Treaty adopted a 12-mile limit to define the seabed area.

The verification provisions also were a subject of intensive discussion. Coastal states were concerned about whether their rights would be protected. Smaller states had doubts as to their ability to check on violations. Some felt that the United Nations should play a larger role. Some wondered whether the verification procedures would really be effective. Reassurances were given to the coastal states. Smaller states could apply for assistance to another state to help it in case of a suspected violation.

The verification procedures are set forth in Article III. Parties may undertake verification using their own means, with the assistance of other parties, or through appropriate international procedures within the framework of the United Nations and in accordance with its Charter. These provisions permit parties to assure themselves the Treaty obligations are being fulfilled without interfering with legitimate seabed activities.

After more than two years of negotiation, the final draft was approved by the U.N. General Assembly on December 7, 1970, by a vote of 104 to 2 (El Salvador, Peru), with two abstentions (Ecuador and France).

Article I sets forth the principal obligation of the Treaty. It prohibits parties from emplacing nuclear weapons or weapons of mass destruction on the seabed and the ocean floor beyond a 12-mile coastal zone. Article II provides that the "seabed zone" is to be measured in accordance with the provisions of the 1958 Convention on the Territorial Sea and the Contiguous Zone. To make clear that none of the Treatys provisions should be interpreted as supporting or prejudicing the positions of any party regarding law-of-the-sea issues, a broad disclaimer provision to this effect was included as Article IV.

In recognition of the feeling that efforts to achieve a more comprehensive agreement should continue, Article V of the Treaty bound parties to work for further measures to prevent an arms race on the seabed.

The Seabed Arms Control Treaty was opened for signature in Washington, London, and Moscow on February 11, 1971. It entered into force May 18, 1972, when the United States, the United Kingdom, the Soviet Union, and more than 22 nations had deposited instruments of ratification.

Article VII included a provision for a review conference to be held in five years. The Seabed Arms Control Treaty Review Conference was held in Geneva June 20 - July 1, 1977. The Conference concluded that the first five years in the life of the Treaty had demonstrated its effectiveness. The Second Review Conference, held in Geneva in September 1983, concluded that the Treaty continued to be an important and effective arms control measure. The Third Review Conference was held in Geneva in September 1989 and confirmed results of previous meetings. It was agreed that the next review conference would be convened in Geneva not earlier than 1996.


1 As noted elsewhere, the Geneva-based ENDC (Eighteen-Nation Disarmament Committee) became known as the CCD (Conference of the Committee on Disarmament) after its enlargement in 1969.

Treaty Text

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

Signed at Washington, London, and Moscow February 11, 1971
Ratification advised by U.S. Senate February 15, 1972
Ratified by U.S. President April 26, 1972
U.S. ratification deposited at Washington, London, and Moscow May 18, 1972
Proclaimed by U.S. President May 18, 1972
Entered into force May 18, 1972

The States Parties to this Treaty,

Recognizing the common interest of mankind in the progress of the exploration and use of the seabed and the ocean floor for peaceful purposes,

Considering that the prevention of a nuclear arms race on the seabed and the ocean floor serves the interests of maintaining world peace, reduces international tensions and strengthens friendly relations among States,

Convinced that this Treaty constitutes a step towards the exclusion of the seabed, the ocean floor and the subsoil thereof from the arms race,

Convinced that this Treaty constitutes a step towards a Treaty on general and complete disarmament under strict and effective international control, and determined to continue negotiations to this end,

Convinced that this Treaty will further the purposes and principles of the Charter of the United Nations, in a manner consistent with the principles of international law and without infringing the freedoms of the high seas,

Have agreed as follows:

Article I

1. The States Parties to this Treaty undertake not to emplant or emplace on the seabed and the ocean floor and in the subsoil thereof beyond the outer limit of a seabed zone, as defined in article II, any nuclear weapons or any other types of weapons of mass destruction as well as structures, launching installations or any other facilities specifically designed for storing, testing or using such weapons.

2. The undertakings of paragraph 1 of this article shall also apply to the seabed zone referred to in the same paragraph, except that within such seabed zone, they shall not apply either to the coastal State or to the seabed beneath its territorial waters.

3. The States Parties to this Treaty undertake not to assist, encourage or induce any State to carry out activities referred to in paragraph 1 of this article and not to participate in any other way in such actions.

Article II

For the purpose of this Treaty, the outer limit of the seabed zone referred to in article I shall be coterminous with the twelve-mile outer limit of the zone referred to in part II of the Convention on the Territorial Sea and the Contiguous Zone, signed at Geneva on April 29, 1958, and shall be measured in accordance with the provisions of part I, section II, of that Convention and in accordance with international law.

Article III

1. In order to promote the objectives of and insure compliance with the provisions of this Treaty, each State Party to the Treaty shall have the right to verify through observations the activities of other States Parties to the Treaty on the seabed and the ocean floor and in the subsoil thereof beyond the zone referred to in article I, provided that observation does not interfere with such activities.

2. If after such observation reasonable doubts remain concerning the fulfillment of the obligations assumed under the Treaty, the State Party having such doubts and the State Party that is responsible for the activities giving rise to the doubts shall consult with a view to removing the doubts. If the doubts persist, the State Party having such doubts shall notify the other States Parties, and the Parties concerned shall cooperate on such further procedures for verification as may be agreed, including appropriate inspection of objects, structures, installations or other facilities that reasonably may be expected to be of a kind described in article I. The Parties in the region of the activities, including any coastal State, and any other Party so requesting, shall be entitled to participate in such consultation and cooperation. After completion of the further procedures for verification, an appropriate report shall be circulated to other Parties by the Party that initiated such procedures.

3. If the State responsible for the activities giving rise to the reasonable doubts is not identifiable by observation of the object, structure, installation or other facility, the State Party having such doubts shall notify and make appropriate inquiries of States Parties in the region of the activities and of any other State Party. If it is ascertained through these inquiries that a particular State Party is responsible for the activities, that State Party shall consult and cooperate with other Parties as provided in paragraph 2 of this article. If the identity of the State responsible for the activities cannot be ascertained through these inquiries, then further verification procedures, including inspection, may be undertaken by the inquiring State Party, which shall invite the participation of the Parties in the region of the activities, including any coastal State, and of any other Party desiring to cooperate.

4. If consultation and cooperation pursuant to paragraphs 2 and 3 of this article 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.

5. Verification pursuant to this article may be undertaken by any State Party using its own means, or with the full or partial assistance of any other State Party, or through appropriate international procedures within the framework of the United Nations and in accordance with its Charter.

6. Verification activities pursuant to this Treaty shall not interfere with activities of other States Parties and shall be conducted with due regard for rights recognized under international law, including the freedoms of the high seas and the rights of coastal States with respect to the exploration and exploitation of their continental shelves.

Article IV

Nothing in this Treaty shall be interpreted as supporting or prejudicing the position of any State Party with respect to existing international conventions, including the 1958 Convention on the Territorial Sea and the Contiguous Zone, or with respect to rights or claims which such State Party may assert, or with respect to recognition or non-recognition of rights or claims asserted by any other State, related to waters off its coasts, including, inter alia, territorial seas and contiguous zones, or to the seabed and the ocean floor, including continental shelves.

Article V

The Parties to this Treaty undertake to continue negotiations in good faith concerning further measures in the field of disarmament for the prevention of an arms race on the seabed, the ocean floor and the subsoil thereof.

Article VI

Any State Party may propose amendments to this Treaty. Amendments shall enter into force for each State Party accepting the amendments upon their acceptance by a majority of the States Parties to the Treaty and, thereafter, for each remaining State Party on the date of acceptance by it.

Article VII

Five years after the entry into force of this Treaty, a conference of Parties to the Treaty shall be held at Geneva, Switzerland, in order to review the operation of this Treaty with a view to assuring that the purposes of the preamble and the provisions of the Treaty are being realized. Such review shall take into account any relevant technological developments. The review conference shall determine, in accordance with the views of a majority of those Parties attending, whether and when an additional review conference shall be convened.

Article VIII

Each State Party to this Treaty shall in exercising its national sovereignty have the right to withdraw from this Treaty if it decides that extraordinary events related to the subject matter of this Treaty have jeopardized the supreme interests of its country. It shall give notice of such withdrawal to all other States Parties to the Treaty and to the United Nations Security Council three months in advance. Such notice shall include a statement of the extraordinary events it considers to have jeopardized its supreme interests.

Article IX

The provisions of this Treaty shall in no way affect the obligations assumed by States Parties to the Treaty under international instruments establishing zones free from nuclear weapons.

Article X

1. This Treaty shall be open for signature to all States. Any State which does not sign the Treaty before its entry into force in accordance with paragraph 3 of this article may accede to it at any time.

2. This Treaty shall be subject to ratification by signatory States. Instruments of ratification and of accession shall be deposited with the Governments of the United States of America, the United Kingdom of Great Britain and Northern Ireland, and the Union of Soviet Socialist Republics, which are hereby designated the Depositary Governments.

3. This Treaty shall enter into force after the deposit of instruments of ratification by twenty-two Governments, including the Governments designated as Depositary Governments of this Treaty.

4. For states whose instruments of ratification or accession are deposited after the entry into force of this Treaty, it shall enter into force on the date of the deposit of their instruments of ratification or accession.

5. The Depositary Governments shall promptly inform the Governments of all signatory and acceding States of the date of each signature, of the date of deposit of each instrument of ratification or of accession, of the date of the entry into force of this Treaty, and of the receipt of other notices.

6. This Treaty shall be registered by the Depositary Governments pursuant to Article 102 of the Charter of the United Nations.

Article XI

This Treaty, the English, Russian, French, Spanish and Chinese texts of which are equally authentic, shall be deposited in the archives of the Depositary Governments. Duly certified copies of this Treaty shall be transmitted by the Depositary Governments to the Governments of the States signatory and acceding thereto.

IN WITNESS WHEREOF the undersigned, being duly authorized thereto, have signed this Treaty.

DONE in triplicate, at the cities of Washington, London and Moscow, this eleventh day of February, one thousand nine hundred seventy-one.

Seabed Arms Control Treaty Signatories

If a scroll bar appears below the following table, swipe the table to move left/right of the dashed line.
Country Date 1 of
Date of
Deposit 1 of
Date of
Deposit 1 of
Afghanistan 02/11/71 04/22/71
Algeria 01/27/92
Antigua & Barbuda 03/21/83 11/16/88
Argentina 09/03/71
Australia 02/11/71 01/23/73
Austria 02/11/71 08/10/72
Bahamas, The 06/07/89
Belgium 02/11/71 11/20/72
Benin 03/18/71 07/02/86
Bolivia 02/11/71
Botswana 02/11/71 11/10/72
Brazil 09/03/71 05/10/88
Bulgaria 02/11/71 04/16/71
Burma 02/11/71
Burundi 02/11/71
Byelorussian S.S.R.2 03/03/71 09/14/71
Cameroon 11/11/71
Canada 02/11/71 05/17/72
Cape Verde 10/24/79
Central African Republic 02/11/71 07/09/81
China, People's Republic of 02/28/91
China (Taiwan) 4 02/11/71 02/22/72
Colombia 02/11/71
Congo, People's
Republic of (Brazzaville)
Costa Rica 02/11/71
Cote d'Ivoire 01/14/72
Croatia* 10/08/91
Cyprus 02/11/71 11/17/71
Cuba 06/03/77
Czechoslovakia 02/11/71 01/11/72
Denmark 02/11/71 06/15/71
Dominican Republic 02/11/71 02/11/72
Equatorial Guinea 06/04/71
Ethiopia 02/11/71 07/14/77
Finland 02/11/71 06/08/71
Gambia, The 05/18/71
German Democratic Republic 02/11/71 07/27/71
Germany, Federal Republic of 06/08/71 11/18/75
Ghana 02/11/71 08/09/72
Greece 02/11/71 05/28/85
Guatemala 02/11/71
Guinea 02/11/71
Guinea-Bissau 08/20/76
Honduras 02/11/71
Hungary 02/11/71 08/13/71
Iceland 02/11/71 05/30/72
India 07/20/73
Iran 02/11/71 08/26/71
Iraq 02/22/71 09/13/72
Ireland 02/11/71 08/19/71
Italy 02/11/71 09/03/74
Jamaica 10/11/71 07/30/86
Japan 02/11/71 06/21/71
Jordan 02/11/71 08/17/71
Kampuchea 02/11/71
Korea, Republic of 02/11/71 06/25/86
Laos 02/11/71 10/19/71
Latvia 08/18/92
Lebanon 02/11/71
Lesotho 09/08/71 04/03/73
Liberia 02/11/71
Liechtenstein 05/30/91
Luxembourg 02/11/71 11/11/82
Madagascar 09/14/71
Malaysia 05/20/71 06/21/72
Mali 02/11/71
Malta 02/11/71 05/04/71
Mauritius 02/11/71 04/23/71
Mexico 3/23/84
Mongolia 02/11/71 10/08/71
Morocco 02/11/71 07/26/71
Nepal 02/11/71 07/06/71
Netherlands 02/11/71 01/14/76
New Zealand 02/11/71 02/24/72
Nicaragua 02/11/71 02/07/73
Niger 02/11/71 08/09/71
Norway 02/11/71 06/28/71
Panama 02/11/71 03/20/74
Paraguay 02/23/71
Philippines 11/05/92
Poland 02/11/71 11/15/71
Portugal 06/24/75
Qatar 11/12/74
Romania 02/11/71 07/10/72
Rwanda 02/11/71 05/20/75
St. Christopher-Nevis 09/19/83 1
St. Lucia 02/22/79 1
St. Vincent and the Grenadines 10/27/79 1
Sao Tome and Principe 08/24/79
Saudi Arabia 01/07/72 06/23/72
Senegal 03/17/71
Seychelles 03/12/85 1
Sierra Leone 02/11/71
Singapore 05/05/71 09/10/76
Slovenia* 04/13/92
Slovak Republic* 10/08/91
Solomon Islands 07/07/78 1
South Africa 02/11/71 11/14/73
Spain 07/15/87
Sudan 02/11/71
Swaziland 02/11/71 08/09/71
Sweden 02/11/71 04/28/72
Switzerland 02/11/71 05/04/76
Tanzania 02/11/71
Togo 04/02/71 06/28/71
Tunisia 02/11/71 10/22/71
Turkey 02/25/71 10/19/72
Ukrainian S.S.R.2 03/03/71 09/03/71
Union of Soviet Socialist Republics 02/11/71 05/18/72
United Kingdom 02/11/71 05/18/72
United States 02/11/71 05/18/72
Uruguay 02/11/71
Vietnam 06/20/80
Yemen Arab Republic (Sanaa) 02/23/71

Yemen, People's
Democratic Rep. of (Aden)

02/23/71 06/01/79
Yugoslavia 03/02/71 10/25/73
Zambia 10/09/72
Total 3 89 66 28

* notification of succession

1 Dates given are the earliest dates on which countries signed the agreements or deposited their ratifications or accessions -- whether in Washington, London, Moscow, or New York. In the case of a country that was a dependent territory which became a party through succession, the date given is the date on which the country gave notice that it would continue to be bound by the terms of the agreement.

2 The United States regards the signature and ratification by the Byelorussian S.S.R. and the Ukrainian S.S.R. as already included under the signature and ratification of the Union of Soviet Socialist Republics.

3 This total does not include actions by the Byelorussian S.S.R. and the Ukrainian S.S.R. (See footnote 2.)

4 Effective January 1, 1979, the United States recognized the Government of the People's Republic of China as the sole government of China.

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