Save Our Seas Act of 2017 or the SOS Act of 2017 This bill amends the Marine Debris Act to revise the Marine Debris Program to require the National Oceanic and Atmospheric Administration (NOAA) to work with: (1) other agencies to address both land- and sea-based sources of marine debris, and (2) the Department of State and other agencies to promote international action to reduce the incidence of marine debris. The bill also revises the program by allowing NOAA to make sums available for assisting in the cleanup and response required by severe marine debris events. NOAA must prioritize assistance for activities that respond to a severe marine debris event in: (1) a rural or remote community, or (2) a habitat of national concern. The bill urges the President to: (1) work with foreign countries that contribute the most to the global marine debris problem in order to find a solution to the problem; (2) study issues related to marine debris, including the economic impacts of marine debris; and (3) encourage the Office of the U.S. Trade Representative to consider the impact of marine debris in relevant future trade agreements. The Interagency Marine Debris Coordinating Committee must expand to include a senior official from the State Department or from the Department of the Interior. This bill reauthorizes for FY2018-FY2022: (1) the Marine Debris Program, (2) an information clearinghouse on marine debris, and (3) enforcement of laws about discarded marine debris from ships.