Very little is actually known about BioShock 2: Sea of Dreams. It was formally announced by Take-Two in March of 2008. No information has been revealed about the game itself, but rumours often that suggest that BioShock 2 will be a prequel to its predecessor. It was announced that development would be handed over to 2K Marin rather than having 2K Boston develop, but Bioshock's director Ken Levine has been confirmed to be working on BioShock 2 but only as the "creative consultant".

PlayStation 3 release of Bioshock

A brief teaser was included in the PlayStation 3 release of BioShock, which revealed the subtitle to be Sea of Dreams.

The first teaser for Bioshock 2 shows a young, possibly adolescent girl dressed in clothes similar to that of a Little Sister. She is holding a Big Daddy doll and standing on a platform jutting out of the sea, somewhere in the Atlantic Ocean. Rock formations then begin to rise out of the water creating a pattern similar to the depiction of Rapture on the logo for the game; the logo itself then fades in. The logo for Bioshock 2 is notably different to the logo for the first game; there are an abundance of barnacles and a Butterfly is seen fluttering around the edges, implying that the Butterfly symbolises something within the game (perhaps metamorphosis or maturity). The subtitle "Sea of Dreams" then fades in below the main title.

The song that is used in the teaser is titled 'Dreams' by the Pied Pipers.