The Trafalgar-class are the successors to the Swiftsure-class and remain the most widely used nuclear attack submarines in the Royal Navy. They were designed as refinements of the Swiftsure boats albiet with noticeably higher displacement, and feature the same coating of anechoic tiles to reduce reflections from active sonar. They are also equipped with a pump-jet propulsion system for additional noise reduction. The Trafalgar-class is designed with five torpedo tubes which can carry a combination of weapons including Spearfish and Tigerfish wire-guided torpedoes as well as Harpoon anti-ship missiles and US Tomahawk cruise missiles. This gives them significant land-attack capability which they have used to good effect in various conflicts. Sensors include a hull-mounted Type 2020 active/passive sonar which was later replaced by the more advanced Type 2074 or Type 2076. Combined with pump jets and anechoic tiles, the Trafalgars are among the quietest nuclear submarines in the world. Various ships in the class have seen extensive action in Iraq, Afghanistan, and Libya primarily for launching Tomahawks. They are expected to be replaced by the Astute-class on a one-to-one basis; the first two ships have therefore already been decommissioned.

Three of the ships have been used to fire Tomahawks in combat: HMS Trafalgar (Afghanistan), HMS Turbulent (Iraq), and HMS Triumph (Afghanistan and Libya). Either HMS Tireless or HMS Turbulent were deployed to the South Atlantic in early 2012 due to increased tension with Argentina over the Falklands. HMS Tireless was also used in the search for missing airliner MH370 in the Indian Ocean.