The Treasure Coast Marine Flea Market and Seafood Festival Announces 2017 Dates, the 4th Annual Event is set for October 14-15 at Indian River Fairgrounds in Vero Beach, Florida. For two days, October 14-15, the 139-acre fairgrounds will be transformed into the Treasure Coast largest nautical ‘Flea Market.’ For boat owners, fisherman, divers and anyone with an interest in things nautical, the Indian River Nautical Flea Market is a bargain hunter&#x27;s dream-come true. Private individuals and ...