To close out an evening after an island tour without much travel, start by comparing Let's Relax Spa Wake Up Ao Nang. It sits in central Ao Nang, walkable from most hotels, and offers a range of programmes including aroma massage and two-hour courses, enough to fill a relaxed Christmas evening.
If you would rather not leave the resort, check Let's Relax Spa - Centara Ao Nang Krabi and Let's Relax Spa - Centara Anda Dhevi Krabi. Each operates inside its namesake resort, so guests can book without a transfer, though couple-room availability differs by property and is worth confirming ahead of time.
For a treatment with a view, Avani Spa at Avani Ao Nang Cliff Krabi Resort is worth comparing too. Set inside the clifftop resort, it pairs a sea view with the treatment, which suits couples wanting something a little more memorable during the Christmas trip.
For a day on land without an island tour, look at Wareerak Hot Spring & Wellness. Combining hot spring bathing with massage gives you a way to fill a day of the trip regardless of the sea conditions.
For a price comparison in central Ao Nang, keep Boossabakorn Spa & Beauty Krabi and Radarom Spa Krabi in mind as well. Both are local spas with different pricing and access than an in-resort spa, useful as a backup if your first choice is booked out. Since Christmas is peak season for popular time slots, reserve an evening or sunset appointment well ahead of your date.