Tonga ratifies CTBT, completing Treaty universalisation in Pacific region
Tonga has ratified the Comprehensive Nuclear-Test-Ban Treaty (CTBT), becoming the 179th State to do so and completing universalisation of the Treaty across the Pacific region. For a part of the world deeply impacted by nuclear testing, it is a milestone long in the making.
The ratification was formalised on 7 July 2026 at a ceremony at United Nations Headquarters in New York, attended by David Nanopoulos, Chief of the Treaty Section, UN Office of Legal Affairs, Permanent Representative of the Kingdom of Tonga to the United Nations, Ambassador Viliami Va’inga Tōnē, and CTBTO Senior Liaison Officer, Charles Abechi Oko.
Robert Floyd, Executive Secretary of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), welcomed the ratification.
“Tonga’s ratification is a proud moment for the Pacific and a meaningful contribution to the global effort to ban nuclear test explosions for good. The Kingdom has long stood on the right side of this issue: as a party to the Treaty of Rarotonga, as a consistent voice for non-proliferation and disarmament, and as a country that understands how nuclear testing has impacted this region. I am deeply grateful to the many Tongan officials and regional partners who worked to bring this moment about.”
UN High Representative for Disarmament Affairs, Izumi Nakamitsu, also underscored the Treaty's importance.
“The CTBT is an integral part of the global disarmament and non-proliferation architecture. It embodies a simple but vital truth: nuclear tests must never be allowed, not even one.”
Tonga’s ratification is the result of sustained engagement between the Tongan leadership, regional partners, and the CTBTO over many years.
This step reflects His Royal Highness Crown Prince Tupoutoʻa ʻUlukalala's strong commitment to international peace and security and demonstrates the leadership needed to advance these shared goals.
Over the years, Floyd has met regularly with senior officials and members of the Tongan Government, including during a mission to the Kingdom in May 2025, when Secretary for Foreign Affairs Viliami Malolo reaffirmed Tonga’s support for the CTBT and its dedication to the Treaty.
At the 80th session of the United Nations General Assembly in September 2025, the CTBTO head met with then-Prime Minister ʻAisake Valu Eke.
Earlier this year, in April, the Executive Secretary met with Ambassador Tōnē on the sidelines of the NPT Review Conference in New York. Ambassador Tōnē, who later deposited the instrument of ratification, has long been a steadfast champion of nuclear non-proliferation and disarmament.
“For Tonga, this is not simply a legal formality. It is a statement of who we are and what we stand for. The Pacific has felt the pain of nuclear testing. Ratifying the CTBT is our contribution to ensuring that no one, anywhere, has to go through that again.”
Tonga is a party to the Treaty of Rarotonga, which established the South Pacific Nuclear-Free Zone in 1985, the second such zone in a populated area of the world, prohibiting the manufacture, stationing, and testing of nuclear explosive devices in member territories. Tonga is also a State Party to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).
With Tonga’s signature and ratification, the CTBT now counts 188 States Signatories and 179 ratifying States. Within the Organization’s broader SEAPFE grouping, which covers South-East Asia, the Pacific and the Far East, just two countries have yet to ratify.
7 Jul 2026