The Jones Act prevents foreign-flagged ships from carrying cargo between the contiguous U.S. and certain noncontiguous parts of the U.S., such as
Puerto Rico,
Hawaii,
Alaska, and
Guam. Foreign ships inbound with goods cannot stop at any of these four locations, offload goods, load contiguous-bound goods, and continue to U.S. contiguous ports, although ships can offload cargo and proceed to the contiguous U.S. without picking up any additional cargo intended for delivery to another U.S. location.
Puerto Rico In June 2012, the
Federal Reserve Bank of New York indicated that the Jones Act may hinder economic development in
Puerto Rico, although a Government Accountability Office report found the effect of repealing or loosening is uncertain, with possible tradeoffs. In March 2013, the
Government Accountability Office (GAO) released a study of the effect of the Jones Act on Puerto Rico that noted, "Freight rates are set based on a host of supply and demand factors in the market, some of which are affected directly or indirectly by Jones Act requirements." The report further concludes that "because so many other factors besides the Jones Act affect rates, it is difficult to isolate the exact extent to which freight rates between the United States and Puerto Rico are affected by the Jones Act." In February 2025, Governor Jennifer Gonzalez-Colón announced a request by the government of Puerto Rico for a permanent exemption from air cabotage laws in Puerto Rico.
U.S. shipbuilding Because the Jones Act requires that all transport between U.S. ports be carried on U.S.-built ships, its proponents claim that it supports the domestic U.S. shipbuilding industry. Shipyards that build Jones Act vessels are needed to build smaller but important government vessels like auxiliary ships, cutters, and research vessels. Jones Act requirements create additional work for these shipyards in between government orders. Proponents say that by keeping the industrial base working, the Jones Act ensures that the Navy and Marine Corps can spin up shipbuilding without relying on other nations. In a 2020 study on the maritime industry, the defense think tank CSBA warned that, without the Jones Act, the shipbuilding industry would face dire impacts, up to and including the inability of the government to purchase any auxiliary ships domestically. Critics of the act describe it as
protectionist, harming the overall economy for the sake of benefiting narrow interests. A 2014 report by
The Heritage Foundation argues that the Jones Act is an ineffective way to promote U.S. shipbuilding, claiming it drives up shipping costs, increases energy costs, stifles competition, and hampers innovation in the U.S. shipping industry. A 2019
Congressional Research Service report stated that U.S. shipbuilding has declined in competitiveness since the law passed. The Organization for Economic Cooperation and Development (
OECD) estimated in 2019 that repealing the Jones Act would boost shipbuilding output by more than $500 million (~$ in ).
National security One main impetus for the law was that, during World War I, belligerent countries withdrew their merchant fleets from commercial service to aid the war effort, leaving the U.S. without enough vessels to conduct normal trade, which impacted the economy. Later, when the U.S. joined the war, there were not enough vessels to transport war supplies, materials, and soldiers to Europe, resulting in the creation of the
United States Shipping Board. The U.S. engaged in a massive shipbuilding effort, including building
concrete ships, to make up for the lack of U.S. tonnage. The Jones Act was passed to prevent the U.S. from having insufficient maritime and shipbuilding capacity in future wars.
Homeland Security The Jones Act includes dredging and salvage operations. Because it creates a domestic dredging and salvage industry in the U.S., it prevents the U.S. from depending on foreign companies to dredge naval facilities, which could create opportunities for sabotage or the depositing of underwater surveillance equipment. Additionally, the requirement that ships in the domestic fleet be crewed by U.S. citizens or permanent residents reduces the likelihood that foreign ships and mariners will illegally gain access to America's inland waterways and associated infrastructure. A 2011 Government Accountability Office (GAO) study found there are about 5 million maritime crew entries into the U.S. each year, and "the overwhelming majority of seafarers entering U.S. ports are aliens." The study showed that 80% of those seafarer aliens work on passenger ships covered by the
Passenger Vessel Services Act of 1886 rather than the Jones Act. The GAO said that while there is no known example of foreign seafarer involvement in terrorist attacks or definitive evidence of extremists infiltrating the U.S. on seafarer visas, "the Department of Homeland Security (DHS) considers the illegal entry of an alien through a U.S. seaport by exploitation of maritime industry practices to be a key concern."
Importation of liquefied natural gas Because of the lack of Jones Act-compliant
liquefied natural gas tankers, the Northeast of the U.S. imported liquefied natural gas from Russia to avoid shortages in 2018.
Restrictions on offshore wind farms The Jones Act has been used by opponents of
offshore wind farms to prevent foreign vessels from constructing and maintaining wind farms near the American coast. , there were no active Jones Act-compliant
wind turbine installation vessels and only one under construction, increasing costs and construction times for offshore wind projects that must use compliant barges to transfer parts to installation ships. A shortage of such vessels was a cause of the cancellation of the
Ocean Wind projects. ==Support==