The festival is organised by Split-based association Cronaves, the City of Stari Grad and the Stari Grad Tourist Board.
Around 50 boats are expected to attend, with up to 60 if weather conditions at sea are favourable, Cronaves president Plamenko Bavčević said.
Italy is this year's partner country, with the Arzana association from Venice set to showcase its maritime heritage.
About 20 members, including boatbuilders, crew members, musicians, poets and cooks, will take part, Bavčević said.
They will form part of a fleet of traditional vessels arriving from across the Adriatic, organised by associations dedicated to preserving Croatia's maritime heritage.
Traditional boats and their crews will showcase maritime and cultural heritage, historic watercrafts, as well as culinary, fishing, boatbuilding and nautical skills.
Crews from Venice, Bar in Montenegro and locations across Croatia have confirmed their participation, including Pula, Opatija, Rijeka, Pašman, Zlarin, Vodice, Betina, Murter, Dubrovnik, Komiža, Split, Trogir, Hvar, Bol, Sućuraj, Vrboska and Stari Grad.