US and UK to begin Trident II D5 Increment 8 in October 2026
An unarmed Trident II D5 Life Extension missile launches from an Ohio-class submarine off the coast of Florida, US in September 2025. (Photo: US Navy)
Trident II D5 Increment 8 will involve improvements to the shipboard navigation subsystem for the US Ohio and Columbia and the UK Dreadnought and Vanguard submarine classes.
The US Navy (USN) and the UK Royal Navy (RN) will start the Increment 8 phase of the UGM-133 Trident II modernisation process next year. This intercontinental submarine-launched ballistic missile (SLBM) is a critical component of the strategic nuclear deterrent for both countries.
According to a notice recently published by the USN, the force plans to award a contract to Lockheed Martin Rotary and Mission Systems (LMRMS) with a performance period starting in October 2026.
Although the USN has not disclosed details about the total value of the agreement, it has allocated nearly US$3 billion to the Trident II life extension programme
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