M51.3

M51.3 is the third version of France's submarine-launched strategic ballistic missile, developed to sustain its oceanic nuclear deterrent against evolving missile defenses.

Overview

The M51.3 is a three-stage, solid-propellant strategic ballistic missile operated by France's Strategic Oceanic Force, or FOST. It belongs to the intercontinental-capability M51 family carried by French nuclear-powered ballistic-missile submarines. According to the French defense procurement agency, DGA, the M51.3 programme, begun in 2014, aims to maintain the sea-based deterrent's capability against the most severe anti-missile defenses.

The version combines the new TNO-2 oceanic nuclear warhead with improvements in range, accuracy and penetration, according to the DGA's M51.3 acceptance-test statement. Operational commissioning was signed on 24 October 2025. Its first submarine launch followed on 6 October 2026, when Le Vigilant fired an unarmed missile after completing an overhaul.

ArianeGroup is the missile's industrial prime. The company describes M51.3 as a progressive replacement for the M51.1 and M51.2 versions already serving aboard France's submarines, rather than a replacement for the entire missile family. The M51 entered service in 2010. M51.3 extends that family while France prepares both another missile upgrade and a successor submarine class.

Image - A Le Triomphant-class ballistic-missile submarine, the class that fires the M51 family. Photo by Marine nationale, Licence Ouverte 2.0, via Wikimedia Commons.

🔒 The full M51.3 file is for BattlePolicy Pro members. Below the line: development history, design and capabilities, variants, the combat record, advantages and limitations, comparable systems, outlook, the full specifications table, our sourcing, and the analyst assessment: procurement, suppliers and the BattlePolicy verdict. Unlock the full file with BattlePolicy Pro →