Phuket is a large island with distinct beach towns, a historic inland centre and busy roads between them. The best base is the district that fits most of your evenings, not the beach with the most appearances on a general highlights list.
Patong has the greatest concentration of nightlife, shopping and services. Kata and Karon remain developed beach bases with a calmer evening rhythm, while northern beaches such as Mai Khao are more spacious and less convenient for frequent trips south.
Rawai is useful for the south and boat connections but is not the same swimming-beach experience. Observe red flags and local warnings; monsoon surf can make a familiar beach unsafe.
Phuket Old Town is the centre for Sino-Portuguese streets, Peranakan heritage and local food. Give it a dedicated morning or evening rather than squeezing it between distant beach appointments.
Offshore trips are weather-dependent and transfers can begin early. Keep one flexible day, confirm the pier and hotel pickup zone, and avoid placing a flight immediately after a boat itinerary.