Captain

From Obsidian Fleet Database

Captain Affiliation Starfleet Higher Rank Commodore Lower Rank Commander Command Starships Starbases Colonies
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Captain (Abbreviated to Capt) is the most senior line officer rank. Captains most often command starships and medium to large starbases. Captains may also command planetary outposts or serve as division heads for Starfleet bases on major worlds or as adjutants to senior flag officers.

Starfleet Officer Ranks
Ensign	Lieutenant JG	Lieutenant	Lieutenant Commander	Commander	Captain	Commodore	Rear Admiral	Vice Admiral	Admiral
For the Starfleet Warrant Officer rank structure click here
For the Starfleet Enlisted rank structure click here