The signature Phuket evening is a show. Phuket Simon Show is a well-reviewed cabaret with fixed sessions that make the evening easy to calculate, while Fantasea Show Phuket pairs a buffet with a large-scale production that works well for families. Siam Niramit Phuket is a staged production on Thai culture, different again in character.
Carnival Magic Phuket is a more recently opened large-scale night theme park format combining performances, a parade and a buffet. It uses the whole evening, so confirm the entry time, programme order and meal inclusion before booking.
For water play, compare Andamanda Water Park Phuket and Splash Jungle Water Park. Andamanda is a more recently opened large park, while Splash Jungle sits in the Mai Khao area, which shortens transfers from airport-area resorts. Both have height-limited rides, so check your child's height.
For an indoor attraction, there is Aquaria Phuket Thailand, an aquarium inside Central Phuket mall, so the plan holds through a wet afternoon and sits on the same route as shopping - a good option to hold for the afternoon of a cancelled boat day.
If you are moving on to Phi Phi or Krabi, Phuket↔PhiPhi Ferry Transfer [Andaman Wave Master] serves as the transfer. As transport rather than an attraction, check departure times, the pier, luggage rules and cancellation terms under sea conditions especially carefully. Before booking anything here, confirm show timetables and seating tiers, meal inclusion, voucher use, height and age rules, whether pickup is included and cancellation terms.