For December 31 daytime, hotel spas come first. Sofitel Sukhumvit offers L'Occitane oils and city views, Sheraton Grande sits near Terminal 21 and allows back-to-back programs in one room, and The Peninsula pairs a riverside setting with Royal Thai massage. They close between 20:00 and 23:00, so fit the time around your countdown evening.
For the evening before midnight, Chi at Shangri-La and DIORA Luxe make a useful contrast. Chi offers firm-pressure Thai massage and its qi programs, while DIORA has 40 oil rooms and stays open until 23:59, which gives groups a wide choice of slots.
After midnight the choices shrink sharply. Makkha Heritage Asoke lists midnight and Signiel Massage in Ekkamai lists 2 a.m., so these are effectively the two places to loosen up right after the countdown. Signiel has only two showers, which must be reserved in advance.
On the morning of January 1, choose among the venues that open at 09:00. Health Land Asoke has 30 single and 56 couple rooms, so even a big group is unlikely to run out of rooms, and DIORA and Makkha start at the same hour. Health Land does not take children under 12, so families should look elsewhere.
Before booking, confirm the last booking time, whether a room is guaranteed and the shower rules on each listing. New Year fares and hours can differ from usual, so treat the current product details as the reference.