See also Recurring characters in the Aubrey–Maturin series
- Jack Aubrey: Captain of HMS Surprise , in Malta for repairs. He sails the East India Company sloop Niobe in the Red Sea.
- Stephen Maturin: Ship's surgeon, friend to Jack Aubrey, natural philosopher and an intelligence officer.
- Sophia Aubrey: Wife of Jack Aubrey and mother of their three children.
- Diana Villiers Maturin: Wife of Stephen and first cousin to Sophia.
- Tom Pullings: Promoted to commander in the Royal Navy on account of the success against two Turkish ships. He is not assigned a ship, but is very happy despite the cruel scars he sustained in the boarding.
- Preserved Killick: Steward to Aubrey.
- Barret Bonden: Coxswain to Aubrey.
- William Mowett: First lieutenant under Aubrey, now that Pullings is promoted.
- Rowan: Second lieutenant under Aubrey, now that Pullings is promoted.
- Mr Peter Calamy: Young midshipman taken on by Aubrey in Worcester and carried to Surprise . He likes Maturin. Part of the mission to the Red Sea.
- Mr Williamson: Young midshipman taken by Aubrey in Worcester and carried to Surprise , where he lost half an arm in the battle with the Turkish ship Torgud . Part of the mission to the Red Sea.
- Mr Honey: Midshipman (master's mate) under Aubrey with enough years of service to take the examination for lieutenant.
- Mr Maitland: Midshipman (master's mate) under Aubrey with enough years of service to take the examination for lieutenant.
- Mr Gill: Master of the Surprise , good at laying a course, but a "melancholy, withdrawn, puritanical" man.
- Faster Doudle: Foremast hand.
- Davis: Foremast hand, very strong but often awkward; he follows Aubrey from ship to ship, on account of Aubrey once saving his life from drowning.
- Mrs Laura Fielding: Young, pretty Neopolitan woman, wife of Charles, a prisoner of war to the French; she was pressed to spy for the French in hopes of his release.
- Charles Fielding: Prisoner-of-war in the worst French prison Bitche, husband of Laura, and lieutenant in the Royal Navy. He escapes Bitche as well, rescued by HMS Nymphe .
- Ponto: Mrs Fielding's huge Illyrian mastiff in Malta, so friendly to Aubrey for pulling him out of a well, that Malta gossips invent another story to account for the friendliness. Dies by poison from a French spy.
- Andrew Wray: Acting Second Secretary of the Admiralty, husband of Fanny Harte, come to Malta to investigate dockyard corruption. He talks with French spy Lesueur and receives money from him. He is in deep debt for losing at cards to Maturin. Maturin observes that, although married to Fanny Harte, Wray is likely a pederast.
- André Lesueur: A French intelligence agent posing as a wealthy merchant on Malta.
- Giuseppe: One of Lesueur's agents.
- Admiral Sir Francis Ives KB: Commander-in-Chief of the Mediterranean Fleet, replacing the late Admiral Thornton in naval and diplomatic matters.
- Admiral Harte: Second-in-Command of the Mediterranean Fleet, father-in-law to Andrew Wray, and recently a wealthy man by an inheritance. He is sent home to England aboard Pollux in company with Surprise , where he dies, at age 67.
- Sir Hildebrand: British Governor of Malta.
- Boulay: Works in Sir Hildebrand's staff, a double agent who talks with Lesueur in Mrs Fielding's residence, as Maturin listens in silence. He is from the Channel Islands.
- Admiral Hartley: Aubrey's former Admiral in the West Indies, now retired in Malta.
- Ebenezer Graham: Professor, expert on Turkish affairs and language, a diplomat and spy in the British service.
- Mr Figgins Pocock: Assistant to the new Admiral on Turkish affairs, pushing Graham back to England.
- Henry Cotton: once a midshipman with Jack, and youngsters together on the Resolution , now captain of the Nymphe
- Heneage Dundas: Captain based in Malta and a close friend to Aubrey. He and Maturin are the first to use the diving bell, off Dundas's ship Edinburgh .
- Mr Hairabedian: Genial Turkish dragoman appointed by the Admiral to accompany Aubrey on the Red Sea mission. He likes to swim from the ship; when he does so in the Red Sea, a shark finds him, shocking even the seamen.
- Mr Nathaniel Martin: Parson from HMS Berwick on leave in Malta, who stays too long on the troop ship with Maturin, thus joins Surprise crew as an assistant to Maturin for the Red Sea mission. He is a natural philosopher. The captain of Berwick is nervous having a parson on his ship when he wants the company of a woman in his bed, which Aubrey knows, so he takes Martin along.
- Major Pollock: Soldier aboard Surprise at her second visit to Kutali, now an English base, with the Adriatic convoy. He reveals to Aubrey that HMS Blackwater is sailing under another captain. (The ship had long been promised to Aubrey.)
- William Babbington: Captain of the Dryad , sailing in company with Surprise back from the Adriatic Sea.
- Dawson: Captain of HMS Pollux , who dies along with all aboard his ship along the Barbary Coast.
