The Offshore Parity Act of 2026 seeks to provide equity to Louisiana, Mississippi, and Alabama by expanding their seaward boundaries in the Gulf of America. This expansion extends the states' jurisdiction from 3 geographical miles to 3 marine leagues for the management of certain submerged lands. The bill's primary purposes are to delegate authority for oil, gas, and other energy activities, and to improve fisheries management within these newly defined state waters, provided states meet specific conditions within five years of enactment. The legislation amends the Outer Continental Shelf Lands Act, allowing the Secretary of the Interior to delegate management of oil, gas, and energy leases in the expanded submerged lands to the states. States must demonstrate adequate resources and effective administration of federal rules, and they will be able to collect revenues from new leases. Additionally, the bill modifies the Magnuson-Stevens Fishery Conservation and Management Act to extend state fisheries management jurisdiction to these 3-marine-league boundaries. Importantly, federal authority over highly migratory species, threatened or endangered species, and national security matters remains preserved.