This bill, titled the "Sanctioning Harborers And Dodgers Of Western Sanctions Act of 2025" or the "SHADOW Fleet Sanctions Act of 2025," seeks to impose robust sanctions on the Russian Federation's "shadow fleet" and associated entities. Its primary purpose is to counter Russia's efforts to circumvent international sanctions, particularly those related to the transport of oil, arms, and other goods. The legislation mandates sanctions on foreign vessels suspected of participating in or supporting the Russian shadow fleet, especially those transporting Russian-origin petroleum products, uranium, or coal while exhibiting unsafe maritime behavior, lacking adequate maritime insurance, or evading the crude oil price cap. Sanctions also target foreign persons who own, operate, or manage such vessels, provide underwriting or insurance services, facilitate deceptive transactions, or offer technology upgrades for sanctions evasion. Furthermore, the bill imposes sanctions on foreign persons who engage in ship-to-ship transfers of Russian-origin products with sanctioned vessels, provide significant support services, or operate foreign ports that allow sanctioned Russian shadow fleet vessels to dock. It specifically allows for sanctions on port terminals in the People's Republic of China or the Republic of India that accept oil from foreign vessels transporting Russian-origin crude oil above the agreed price cap or from vessels already subject to U.S. sanctions. To enhance enforcement, the bill requires alignment of designation authorities with the European Union and the United Kingdom regarding the Russian shadow fleet. It also calls for the establishment of a public database of foreign vessels involved in sabotage or other illicit activities and supports the efforts of the Joint Expeditionary Force in tracking and deterring such operations. The legislation outlines minimum standards for countries operating as flag state registries, emphasizing the need to prevent the use of their flags for sanctions circumvention, illicit activities, and unsafe maritime practices. It mandates a strategy for engaging with countries that fail to meet these standards. Regarding Russian-origin oil, the bill directs the Secretary of State and Treasury to monitor international compliance with the crude oil price cap, engage foreign governments, and identify entities evading the cap. It also requires regular reports on Russian oil exports, income derived, and efforts to prevent the importation of such products into the United States. A significant provision addresses the role of the People's Republic of China in evading sanctions on Russian-origin petroleum products. The bill mandates a strategy to strengthen enforcement, expand sanctions designations targeting Chinese involvement in the production, transportation, and sale of these products, and assess the impact of smuggled Russian oil on global markets. Sanctions are also extended to foreign persons who sell, lease, or provide goods or services relating to Russia's defense industrial base, including critical technologies like CNC tools, semiconductors, and nitrocellulose. Identified individuals and corporate officers of sanctioned entities face visa ineligibility and revocation, and their property in the U.S. is subject to blocking. General provisions detail the types of sanctions, including the blocking of property and visa restrictions, while outlining exceptions for humanitarian aid, vessel safety, and intelligence activities. The bill also includes waiver mechanisms for national security interests or if sanctioned parties cease their illicit activities. Finally, it addresses other matters such as determining Russian military actions in the Baltic, increasing resources for sanctions implementation at the Department of State, and reporting on U.S. assistance to Ukraine.