Gearbox Software has released a trailer for the DLC pack, introducing the titular character and the expansion's new areas.
The pack adds new characters, enemy types, vehicles, weapons and challenges to the campaign.
It follows the addition of the Mechromancer class, which was released last week.
"We're so excited at how the Borderlands 2 experience continues to grow with Captain Scarlett and her Pirate's Booty and the fifth playable character class, the Mechromancer," said 2K Games president Christoph Hartmann.
"With hours of new story-driven content to play through and an entirely new character to play as, gamers are getting a lot of additional value. The really exciting part is that we're just getting started."
> Read our hands-on preview with the 'Captain Scarlett and Her Pirate's Booty' DLC
Copyright: 2K GamesThe pack is the first of four pieces of campaign DLC releasing between now and June 2013.
It can be purchased individually, or with the discounted Borderlands 2 season pass.
Each pack costs $9.99 (£6.30) on PC and PS3 and 800 Microsoft Points (£6.80 / $10) on the Xbox 360.
The Season Pass, meanwhile, can be picked up for $29.99 (£18.90) on PS3 and PC, and 2400 Microsoft Points (£20 / $30) on Xbox 360.
Released last month, Borderlands 2 was the biggest-selling launch of the year until the release of FIFA 13.
> Read Digital Spy's Borderlands 2 review
Watch the launch trailer for Borderlands 2 below: