For proper seafood, Bubbles Restaurant at Grand Mercure Phuket Patong is the leading candidate, serving a seafood BBQ at a Patong-area hotel restaurant, with strong review volume and scores and a short transfer if you are staying in Patong. Confirm service hours and adult or child pricing before booking.
For Thai fine dining, compare Blue Elephant Restaurant - Phuket, which serves classical Thai courses in a mansion building in Phuket Old Town, a fit when you want more formality for the holiday meal. Set Lunch and Set Dinner at Three Monkeys Restaurant is the option for Thai food in a more relaxed setting.
To spend the evening with a sunset, look at [Royal Phuket Cruise] Sunset Dining Cruise, which serves dinner on the water as the light goes over the Andaman - a fit when you want one standout evening. Sailings can change with sea state in the Chuseok travel period, so check cancellation rules carefully.
To keep everything inside the resort, compare the outlets at Diamond Cliff Resort & Spa. Set Menu at Sea Salt Lounge & Grill covers a formal dinner, Afternoon Tea Set at Sea Salt Lounge & Grill covers the afternoon, and Set Menu at FUGA Beach Club covers a beachside mood - so you can pick the time and atmosphere within one property.
For a local seafood restaurant, Set Menu at Kan Eang at Pier is worth considering, near Chalong Pier, when you want something other than a tourist-centre venue. Before booking, confirm the reservation method and service hours, set structure and pricing, dress code, wet-weather policy for outdoor seating, and cruise boarding location and cancellation rules.