Discovered earlier this week, 'Captain Scarlett and Her Pirate's Booty' takes place in an expansive desert, which houses a shanty town called Oasis.
Centred around a one-eyed pirate named Captain Scarlett, the campaign introduces a new sand skiff vehicle, as well as enemies such as sand worms. It also features a new currency called seraph crystals.
Likening the new environment to Tatooine from Star Wars, Gearbox president Randy Pitchford said: "You can sense the pirate theme across the landscape, even though there's no water.
"It's all dried up. It feels more like Tatooine than an ocean. These bandits have really embraced the pirate lifestyle, and there's the legend of a treasure. That kicks off this whole adventure that the players can go on."
The 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: