The Ensuring Naval Readiness Act would modify federal law to allow the U.S. Navy to build naval vessels in foreign shipyards under specific conditions. Currently, federal law generally prohibits this practice, but this bill creates an exception when the foreign shipyard is located in a NATO member country or an Indo-Pacific nation with a mutual defense treaty with the United States, and when building abroad would cost less than building in domestic shipyards. Before construction can begin at any foreign facility, the Secretary of the Navy must certify to Congress that the shipyard is not owned or operated by Chinese companies or multinational firms based in China. The bill affects U.S. military shipbuilding operations and defense contractors, potentially allowing the Navy to expand its construction options while maintaining national security safeguards. No specific funding amounts or implementation timelines are outlined in the legislation.