HMS Achilles (also known as Astute Boat 7) is an Astute-class nuclear-powered fleet submarine under construction for the Royal Navy and the seventh in her class.

[9][10] The confirmation for the seventh and final Astute-class boat was given in the Strategic Defence and Security Review 2010, although the order was not placed until 2018.

Since the submarine can replenish her air supply and purify water underway and while submerged, she will be able to circumnavigate the planet without resurfacing.

The submarine's main limitation will be from the three months supply of food carried for the 98 officers and ratings.

[17] The submarine will be capable of using Tomahawk Block IV land-attack missiles with a range of 1,000 miles (1,600 kilometres)[18] and Spearfish heavyweight torpedoes.