Staying in Patong gives you the widest choice. Orientala Spa Phuket Patong has good access in central Patong and a high review count, which makes it easy to place in an evening. Kim's Massage & Spa Patong Beach Phuket is worth noting when weighing price against access.
For the settled programmes of a chain, compare the Let's Relax properties. Let's Relax spa at 3rd Street branch Phuket has good Patong access, while Let's Relax Phuket Porto de Phuket pairs with plans around Laguna and Bang Tao. Fixed programme lengths make scheduling easy to calculate.
For an established spa setting, the Oasis Spa properties are worth considering. Oasis Spa Tropical Retreat Spa, Laguna covers the Laguna estate side, Oasis Spa Sky Breeze Kata beach Phuket the Kata side, and Oasis Spa Turquoise Cove Spa Kamala Phuket the Kamala side - so you can stay within one brand and still match your area.
If you are based around Kata or Karon, De Flora Spa Phuket is another candidate. On a day tired out by an island tour, choosing somewhere close to the resort removes the evening transfer and helps recovery. Check programme structure, duration and couple room availability in the product details.
Before booking, confirm programme duration and price, how to reserve and when to arrive, which areas resort pickup covers, couple or private room availability, shower facilities, tipping practice and the cancellation window. Evening slots fill first during this holiday, so use the current product details as the final reference.