In 2016-2017 Public Health Seattle King County (PHSKC) investigated the source of two reported cases of Vibrio vulnificus. Both case-patients sustained wounds while handling tilapia, a freshwater fish, purchased live from 2 retail fish markets before illness onset. PHSKC inspected both retail fish markets where patients purchased live tilapia ("Market A" and "Market B") and transport tanks from a common distributor. Fish specimens and swabs from fish tanks, utensils, and environmental surfaces were collected. V. vulnificus was identified from 2/2 fish and 7/7 environmental swabs collected from "Market A" where "Patient A" shopped, and 2/2 fish and 6/8 environmental swabs from "Market B" where "Patient B" shopped, and 1/2 fish and 3/5 transport tanks from "Distributor A". PFGE patterns differed between patients but matched investigation isolates; 3 environmental isolates from "Market A" matched "Patient A's" isolate and all isolates from "Market B" and "Distributor A" matched "Patient B's" isolate.