| The Captain - Popular with his crew, self-assured and perhaps a bit stuffy. His second act solo "Fair Moon" is lovely and a bit challenging to carry off. |
| Sir Joseph Porter, KCB - A stuffy martinet. The First Lord of the Admiralty, a political appointee, who knows nothing about the Navy and has never been to sea. A comic role. (Based on W H Smith, the bookstore magnate, who was appointed to this position.) He was thereafter known as "Pinafore Smith." |
| Ralph Rackstraw - (pronounced "Rafe") An able bodied seaman who loves the Captain's daughter. A challenging tenor role, that requires good acting skills. |
| Josephine - The Captain's daughter. A coloratura soprano with a mind of her own, but who loves her father as well as loving Ralph. |
| Dick Deadeye - A seaman who comments subversively on the fact that class is still important. Needs to be able to sing through and over the chorus singing full-tilt. |
| Little Buttercup - A "Portsmouth Bumboat Woman," who sells trinkets to the sailors and secretly loves the Captain. Can be comic. |
| Cousin Hebe - Often played as the "head cousin" of the women's chorus, who leads the women's chorus about. Ends up with Sir Joseph. |
| Bosn's Mate - Represents the crew's thoughts and feelings. Has a number of lines and sings in the "A British Tar" trio. |
| Carpenter's Mate - Sings in the "A British Tar" trio, but has no lines. |
Trial by Jury is a 35-minute curtain raiser with no dialog. All the characters sing their roles and must be able to so do convincingly.
| The Learned Judge -Comic baritone - Another political appointee with only limited actual knowledge and ability. Generally a comic role. |
| The Plaintiff, Angelina. - A soprano role. The poor girl has been thrown over by Edwin and is suing him for breach of promise of marriage. |
| The Defendant, Edwin - A tenor. A thorough-going cad, who loved this lady today and the other tomorrow. |
| Counsel for the Plaintiff- Tenor - Represents Angelina's pleadings in a somewhat comic ballad. |
| Usher -Baritone-- Baritone or Bass - Runs the courtroom, sings a few lines by himself and in several ensembles. |
| Foreman of the Jury --Bass- Sings a few lines in several songs. |