Sighting and stranding data are often used to identify patterns in marine mammal occurrence. Here we evaluate the use of public sighting reports, systematic surveys (where available), and stranding data from 1995-2015 to test how well these reflect trends in nine cetacean species in Puget Sound, Washington, USA. In general we found good agreement in documenting trends in occurrence between one of the sighting sources and strandings for 7 of 9 species, though there were often some species-specific considerations.