The United States Navy conducted four test launches of unarmed Trident II D5 Life Extension (D5LE) missiles from an Ohio-class ballistic missile submarine in the Atlantic Ocean off the Florida coastline, according to the service’s Strategic Systems Programs (SSP). The September 2025 flights validated performance of the D5LE system and brought the program’s total successful flight tests to 197, the Navy said.
Navy officials said the launches were part of recurring testing to ensure reliability and accuracy and were not in response to any specific world event.
“Our nation’s submarine-launched ballistic missile system has been a critical component of our national security since the 1960s, and these launches continue to demonstrate the credibility and reliability of our strategic deterrence capabilities,” said U.S. Navy Vice Adm. Johnny Wolfe, director of the SSP, which is responsible for Naval strategic weapons, according to a news release.
The Trident II D5 is a three-stage intercontinental ballistic missile (ICBM) deployed on Ohio-class and United Kingdom Vanguard-class ballistic missile submarines (SSBN). The missile can travel about 12,000 kilometers and is compatible with multiple reentry vehicles that can carry up to eight warheads under current treaty limits, according to the Center for Strategic and International Studies missile threat database. The D5 underwent a life-extension program that was completed in 2017 to modernize guidance, propulsion and other components and extend service into the 2040s, according to the Navy.
SSBNs and their Trident missiles form the sea leg of the U.S. nuclear triad, which provides a survivable and constant deterrent. Navy officials emphasized that recurring flight tests are central to demonstrating readiness and to assuring U.S. Allies that the sea-based deterrent remains effective. Analysts say the combination of range, mobility and accuracy make SSBNs and Trident missiles a uniquely stabilizing element of strategic deterrence because submarines are difficult to find and target. The tests came as China and Russia modernize their nuclear arsenals and global arms-control arrangements are in flux.
“Maintaining our current capability and actively demonstrating through flight testing that the system is ready to respond if called upon is central to ensuring our nation’s peace through strength,” Wolfe said in the SSP news release. “The team is also pushing ahead developing the next-generation strategic weapon system to ensure the sea-based deterrence capability of tomorrow.”