See also Recurring characters in the Aubrey–Maturin series
- Jack Aubrey: Royal Navy lieutenant newly appointed Master and Commander of Sophie ; addressed as "Captain".
- Stephen Maturin: Physician and natural philosopher, musician, stranded when his patient dies, taken on as surgeon when Jack Aubrey begins as captain of Sophie .
- Harte: Captain and station commandant at Port Mahon, with a strong grudge against Aubrey.
- Molly Harte: Wife of the station commandant, and lover of Aubrey.
- Lord Keith: Admiral in the Mediterranean, recently married to Queeney
- Queeney: Recently wife of Lord Keith, and in earlier days, neighbour and tutor to young Jack Aubrey, and he suspects, the reason for his promotion.
- Samuel Allen: Erstwhile captain in Sophie , succeeded by Aubrey.
- Mr Baldick: Lieutenant in Sophie , ill and replaced.
- Mr Williams: Administrator in Mahon for Aubrey's prize-agent.
- David Richards: Relative of Mr Williams who serves as clerk in Sophie .
- William Marshall: Master in Sophie .
- Tom Pullings: Master's mate in Sophie , who has passed his examination for lieutenant, but awaits promotion.
- William Mowett: Master's mate in Sophie .
- Isaac Wilson: Ordinary seaman in Sophie .
- Watt: Bosun in Sophie .
- Barret Bonden: Young and highly competent, valued coxswain and captain of the maintop in Sophie .
- Lamb: Ship's carpenter.
- Ricketts: Purser and father of young Ricketts.
- George Day: Gunner.
- Charles Stephen Ricketts: Son to the purser, rated midshipman.
- Mr William Babbington: Midshipman in Sophie , young but already quite the ladies man.
- Mr James Dillon: First lieutenant in Sophie , valued for his skills and letting Aubrey leave day to day issues to him. Known to Maturin from his days in Ireland.
- Alfred King: Black crew member, also a mute, brought by David Richards.
- Quinn: Sergeant of marines.
- Lieutenant Dalziel: Replaces Lieutenant Dillon, despite a nomination of Pullings for promotion.
- Captain Heneage Dundas: Captain of the sloop Calpe and friend of Aubrey.
- Captain Christy-Pallière: Captain of the French ship Desaix who takes Sophie , and all her crew as prisoners. He is a good seaman, and a good host to his prisoners.
- Admiral Sir James Saumarez: Rear Admiral of the squadron that wins out in the Algeciras Campaign, after first losing to the French fleet. He speaks with Aubrey in Gibraltar, where Aubrey is released on his parole, reminding him he cannot wear his returned sword until after the court martial for losing HMS Sophie . He listens to what Aubrey learned as prisoner of war aboard the French Desaix .
