Patong is where the Songkran water fight burns hottest in Phuket. A spa here is not a break from the festival but the recovery that lets you join in again tomorrow, so favour places you can walk to from the action.
Midday in Phuket in April reaches 35 to 40 degrees. If you play in the water in the morning and cool down in the afternoon, Spring, which opens at 13:30, or Sansabai 3 inside Jungceylon fits well.
Check what is open when the water fight ends. Vimaan stays open until 23:45 and Karahill and Makkha Arches until midnight, while Orientala at Deevana Plaza closes at 19:00 and belongs in the daytime before the festival evening.
For a big group, room count is the measure: Sansabai 3 has 13 rooms and the Beyond Resort branch seven couple rooms. With children, check age rules such as the 3 to 11 range at Diwa and Karahill on each listing.