See also Recurring characters in the Aubrey–Maturin series
- Jack Aubrey: Captain of the Surprise , a letter of marque sold out of the Royal Navy, and he is off the Navy List.
- Stephen Maturin: Ship's surgeon, natural philosopher, friend to Jack and an intelligence officer.
- Sophia Aubrey: Wife of Jack Aubrey and mother of their three children.
- Charlotte, Fanny and George Aubrey: The three children of Jack and Sophia.
- Philip Aubrey : Jack's much younger half-brother, who comes home from school for the funeral of their father.
- Diana Villiers: Stephen's estranged wife.
- Sir Joseph Blaine: In the Admiralty and restored to his position; entomologist; active in intelligence.
- Mr Nathaniel Martin: Recently married parson and natural philosopher whom Maturin takes on as his assistant on the Surprise , now a letter of marque. He will never serve in the Royal Navy again, on account of a pamphlet he wrote that was critical of certain practices in the Navy.
- Preserved Killick: Steward to Aubrey.
- Barret Bonden: Coxswain to Aubrey.
- Joe Plaice: Able seaman, older cousin to Bonden. He falls overboard on Surprise but is saved by someone from the Merlin , a captured vessel under Pullings's command. He takes part in the cutting out of the French frigate Diane in her harbour.
- Padeen Colman: Stephen's Irish servant; loblolly-boy on the Surprise .
- Monsieur Duhamel: French intelligence agent who dies during the boarding of HMS Eurydice , by a fall in rough waters, weighted down by all his money in gold wrapped around his body. He kept the promise he made to Maturin in The Surgeon's Mate .
- Captain Tom Pullings: He is First Mate on the letter of marque Surprise and half pay commander in the Royal Navy.
- William Mowett: Aboard Tartarus en route to his position as first lieutenant of HMS Illustrious , oddly called James by Maturin when they meet aboard Tartarus ; waiting for his book of poems to be printed, has a new poem. Pullings, Babbington and Mowett had been midshipmen on Aubrey's first command.
- Captain William Babbington: Captain of HMS Tartarus ; commander of the St Martin blockading squadron; made Post Captain; lover of Fanny Wray.
- Fanny Wray: Daughter of Admiral Harte and wife of Andrew Wray, now sailing with Babbington.
- Andrew Wray: He once worked in the Admiralty and the Treasury under the tutelage of Ledward; a French agent who has fled the country.
- Edward Ledward: Once worked in the Treasury; a French agent who has fled the country.
- The Duke of Clarence: The Prince Regent's younger brother.
- Paul Ségura: French agent and sea officer aboard the Diane , taken prisoner by Maturin. He escapes when the imprisoned women are freed, disguised as one, to the chagrin of Maturin, who was treating patients. He is also known as the Red Admiral among intelligence agents.
- Mrs Broad: Landlady of The Grapes, now rebuilding.
- Mr Davidge: Third Mate in the letter of marque Surprise . He attended Trinity College in Dublin like Maturin, and knew the same amount of duelling in those years. He had been a Royal Navy lieutenant
- Mr West: Second Mate the letter of marque Surprise . He had been a Royal Navy lieutenant.
- Slade: Crew member of the Surprise and one of nine who is a Sethian (a religious group); after the first successful voyage, they painted Seth on the side of Surprise .
- Heneage Dundas: Friend to Aubrey, captain of HMS Eurydice , brother to Lord Melville. He talks to Aubrey after the latter gains his seat in Parliament, and assures his brother that Aubrey has no intention of speaking up in the way his father did.
- Lord Melville: First Lord of the Admiralty and brother to Heneage Dundas.
- Mr Pratt: Private investigator who seeks General Aubrey, and does find him in the north of England. Pratt aided Jack Aubrey's case in The Reverse of the Medal .
- Edward Norton: Owner of neighboring lands to Aubrey's boyhood home of Woolcombe, and a friend to his grandfather. In childhood, Aubrey called him cousin Edward. Norton owns all the land for the borough of Milport, thus he can assure who will be the member of Parliament from there.
- Gedymin Jagiello: Lithuanian, recently promoted to Colonel in the Swedish army, who works with the foreign office in Stockholm, soon to be married. He was introduced in The Ionian Mission .
- Countess Tessin: Jagiello's grandmother.
- Mersennius: Doctor who treats Maturin after his fall, dealing with the laudanum addiction.
- Mr Standish: Newly hired purser for Surprise , a friend of Martin. Sophia Aubrey teaches him, double checks his sums. He trained for a parson, as that is what his family wants, but he wants to be at sea.
