This legislation, known as the Great Lakes Icebreaker Act of 2025, mandates that the Commandant of the Coast Guard submit a comprehensive strategy within 90 days of enactment. This strategy must detail how the Coast Guard will complete the design and construction of a new Great Lakes icebreaker, which must be at least as capable as the Coast Guard cutter Mackinaw (WLBB-30) . The plan is required to include a cost estimate and an estimated delivery timeline designed to facilitate expedited delivery once funding is secured. The bill also establishes a five-year pilot program to evaluate the effectiveness of the Coast Guard's Great Lakes icebreaking cutter fleet. This program will determine the fleet's capability to keep tier one and tier two waterways open 95 percent of the time during ice seasons. Following each of the five ice seasons, the Commandant must submit a report to Congress detailing the pilot program's results and any new performance measures implemented by the Coast Guard, including those outlined in a previous report on domestic icebreaking operations. Furthermore, the Act modifies existing reporting requirements concerning Coast Guard icebreaking activities. It amends the Don Young Coast Guard Authorization Act of 2022 to require the Commandant to publish a public report on the cost of meeting proposed icebreaking standards. The bill also mandates that the Commandant provide briefings to congressional committees on the cost of meeting specific icebreaking requirements for fiscal years 2024, 2025, and 2026, as outlined in the James M. Inhofe National Defense Authorization Act for Fiscal Year 2023.