Gulf Coast Oil Spill Legal Liabilities and Claims Act of 2010

Gulf Coast Oil Spill Legal Liabilities and Claims Act of 2010 - Prohibits settlement, legal release, or other agreement from extinguishing or limiting liability in a civil action for significant harm arising from a discharge into waters off the shore of the United States of a substance that contaminates a marine or coastal environment or endangers public health, if such settlement, legal release, or agreement is entered into under coercion or duress or is entered into in exchange for any benefit other than a settlement of claims pending.

Amends the Class Action Fairness Act of 2005 to exclude from class actions under such Act any action brought by a state or one of its subdivisions on behalf of its citizens.

Amends the federal judicial code to exclude an action brought by a state or one of its subdivisions on behalf of its citizens from the meaning of a class action or mass action.