Offshore Fairness Act - Amends the Submerged Lands Act to extend the seaward boundaries of Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, and Virginia to a line three marine leagues (currently, three geographic miles) distant from the coast line.

Directs the Secretary of the Interior to: (1) notify such states of the right to request a conveyance of the applicable interest of the United States in and to the expanded submerged land; and (2) at such a state's request, convey to the applicable state the interest of the United States in and to such land.

Prohibits states conveyed such land from imposing: (1) burdens or requirements on an interest owner that would be stricter than any federal burdens or requirements, and (2) administrative or judicial penalties or sanctions on an interest owner that are more severe than any federal administrative or judicial penalty or sanction.

Declares submerged land within the seaward boundaries of such states to be subject to federal oil and gas mineral rights and to be considered part of the federal outer continental shelf for purposes of the Outer Continental Shelf Lands Act, the Gulf of Mexico Energy Security Act of 2006, and other laws applicable to the leasing of the oil and gas resources.

Prohibits this Act from affecting any federal oil and gas lease in effect on the date of the land conveyance. Excludes from specified requirements and prohibitions any interest in the expanded submerged land that is granted by the state after the date on which the land is conveyed.

Authorizes such states to exercise their sovereign taxation powers within the entire extent of the extended seaward boundaries. Prohibits this Act from affecting a state's authority to tax any federal oil and gas lease in effect on the date of enactment of this Act.

Directs the Secretary of Commerce to grant such states exclusive fishery management authority over: (1) reef fish in the Gulf of Mexico and the Atlantic Ocean in the expanded submerged land, (2) red snapper fish in designated areas until the state's governor certifies that the stock assessments of the National Oceanic and Atmospheric Administration (NOAA) are accurate and based on sound science.