Pirate Captain

The title of Captain can refer to either a Captain of a pirate crew, or a rank in the Marines (note however, that this is meanly a coincidence in the English translation, as Japanese words for the two are not the same).

Pirate Captains
Pirate Captains are the ones who are at the very head of a Pirate crew. Pirating captains also tend to be the mightiest members of their crew, and most of them tend to exploit their strength even over their own subordinates to ensure loyalty; though not necessarily, as anyone can attain the rank of captaincy out of pure leadership or even as a founding member. All major decisions are made by them.

List Of Pirate Captains

 * Gol D. Roger (Captain of the Jolly Roger Pirates, deceased)
 * Alvida (former Captain of the Alvida Pirates, second Captain of the Buggy Pirates)
 * Monkey D. Luffy (Captain of the Straw Hat Pirates)
 * Red-Haired Shanks (Captain of the Red-Haired Pirate Crew)
 * Buggy the Clown (Captain of the Buggy Pirates)
 * Kuro (former and renewed Captain of the Black Cat Pirates)
 * Don Krieg (Admiral of the Don Krieg's Pirate Armada)
 * Jinbei (second Captain of the Sunny Pirates, temporarily incarcerated)
 * Arlong (Captain of the Arlong Pirates, incarcerated)
 * Edward Newgate (Captain of the Whitebeard Pirates)
 * Marshall D. Teach (Captain of the Blackbeard Pirates)
 * Macro (Captain of the Macro Fishman Pirates)
 * Bellamy (Captain of the Bellamy Pirates)
 * Montblanc Cricket (Leader of the Saruyama Alliance)
 * Masira (Captain of one portion of the Saruyama Alliance)
 * Shoujou (Captain of one portion of the Saruyama Alliance)
 * Foxy the Silver Fox (Captain of the Foxy Pirates)
 * Mikazuki (Captain of the Big Helmet Pirates)
 * Yorki (first Captain of the Rumbar Pirates, deceased)
 * Lola (Captain of the Rolling Pirates)
 * Capone Bege (Captain of the Firetank Pirates)
 * Jewelry Bonney (Captain of the Bonney Pirates)
 * Eustass Kid (Captain of the Kid Pirates)
 * Scratchmen Apoo (Captain of the On Air Pirates)
 * Basil Hawkins (Captain of the Hawkins Pirates)
 * Urouge (Captain of the Fallen Monk Pirates)
 * X. Drake (Captain of the Drake Pirates)
 * Trafalgar Law (Captain of the Heart Pirates)
 * Boa Hancock (Captain of the Kuja Pirates)
 * Fisher Tiger (first Captain of the Sunny Pirates, deceased)

Former Pirate Captains

 * Jango (was second Captain of the Black Cat Pirates, now a member of the Marines)
 * Wapol (became Captain of Wapol Pirates while in exile due to the Blackbeard Pirates, now a CEO of his own toy company)
 * Fanged Toad Pirates Captain (now in Foxy Pirates)
 * Brook (was Captain of the Rumbar Pirates, now in Straw Hat Pirates)
 * Dias (was Captain of the Acumate Pirates, now in custody of the Marines)
 * Jean Bart (was Captain of an unknown crew, now in Heart Pirates)

Marine Captains
A Marine Captain (大佐) is a rank junior to that of a Commodore. It is second most seen rank in One Piece to date, having 8 representatives and being second only to that of Vice Admiral in terms of appearance. The number of seen captains MAY have surpassed the number of seen vice admirals, during the Enies Lobby assault on the Bridge of Hesitation, where no one below the rank of captain was to attack, we have not seen many of them more then once and only from from afar, except three (Sharingu, Shuu, Very Good) however, these were never specifically referred to as "captains", until being dubbed as such by Oda in the SBS of volume 47.

Trivia
Any naval officer below the rank of captain who commands a ship, is addressed as "captain" while aboard that ship, by naval custom. The ship's captain also may be referred to as the Skipper. A naval officer with the rank of captain traveling aboard a vessel he does not command is either never referred to by rank, or in some navies, is addressed as Commodore to avoid confusion with the ship's actual commander.

Current

 * Hina
 * Nezumi
 * T-Bone
 * Very Good
 * Sharingu
 * Shuu

Former

 * Smoker-promoted to Commodore
 * Morgan-discharged from the Marines

Commanding officers
Another position in the marines that is translated as captain, but different from the Taisa (大佐) rank is the Taichō (隊長) title, meaning captain or commanding officer. The marines that have this title are not the type of captain that's listed as a marine rank.
 * Attachan
 * Sentoumaru