The "Offshore Energy Security Act of 2025" mandates the Secretary of the Interior to conduct a significant number of offshore oil and gas lease sales. Specifically, it requires at least 20 offshore lease sales over a 10-year period, beginning from the date of the Act's enactment. These sales must occur twice annually, following a strict schedule from March 2026 through August 2035. Each mandated offshore lease sale must offer a minimum of 74,000,000 acres for lease. All sales are to be located within the Gulf of Mexico Region Program Area and must adhere to the lease form, terms, and economic conditions established in the "Gulf of Mexico Outer Continental Shelf Oil and Gas Lease Sale 261" notice. The Secretary is also granted authority to waive certain requirements under the Outer Continental Shelf Lands Act to prevent delays in the final approval of these sales. A key provision addresses the impact of litigation, stating that civil actions related to environmental reviews under the National Environmental Policy Act (NEPA) for these sales shall not affect the validity of issued leases or delay the processing of drilling permits. If a court finds a NEPA violation, it must remand the matter to the Secretary for resolution rather than vacating the leases. Leaseholders are also given the option to pause their lease terms during pending litigation. The bill also amends the Gulf of Mexico Energy Security Act of 2006 by extending the moratorium on oil and gas leasing in certain areas, such as the Eastern Gulf of Mexico, from June 30, 2022, to December 31, 2035. It further expands this moratorium to include the South Atlantic Planning Area and the Straits of Florida Planning Area . However, the bill clarifies that these moratoria do not affect valid existing leases and introduces an exception allowing the Secretary to issue leases in these areas for environmental conservation purposes, including shore protection and wetlands restoration.