Efforts are underway to restore the Salish Sea, a 16,925 km² inland sea shared by Washington State, USA, and British Columbia, Canada. A list of the birds and mammals that use this marine ecosystem is lacking. We compiled information from varied sources and identified 172 bird and 37 mammal species that depend on the Salish Sea marine ecosystem. Of these species, 72 bird and 29 mammal species are both highly dependent on intertidal or marine habitat as well as on marine derived food. One hundred bird species and 8 mammal species that use the Salish Sea marine ecosystem have varying degrees of dependence on the marine and terrestrial ecosystems to meet significant life history needs. These interactions between the marine and terrestrial ecosystems indicate the need to integrate marine and terrestrial restoration efforts to achieve long-term conservation of the suite of birds and mammals that use and depend on the marine ecosystem. This comprehensive list of avian and mammal fauna for the Salish Sea serves as a foundation for determining the occurrence of new species and the disappearance of others, enables selection of species as indicators for ecosystem health, and also provides a basis for identifying the mechanisms responsible for marine bird and mammal declines.