In-Person: Trader Joe’s, Whole Foods, or try your favorite grocery store. (I will personally say I do not like the quality of ahi tuna from Trader Joe's.) Thrive Market sells frozen ahi tuna steaks (that is where I prefer to purchase). Catalina Offshore Products, based in San Diego, CA, is one of SoCal’s premier fresh and frozen seafood. They deliver to almost anywhere in the United States.