December 31 daytime suits tours that return by 15:00-16:00. The Prachuap Khiri Khan private tour (leaving 08:30, back at 15:00) and the Phetchaburi temple and palace join tour (back at 15:00) include admissions and lunch, and the Pala-U waterfall tour returns at 15:30. Keep the evening free for your hotel's year-end program.
For active groups there is the Pala-U waterfall tour: the 12-meter Luang Pu Thuat statue at Wat Huay Mongkol, then about 45 minutes on foot through Kaeng Krachan National Park to the falls. The Huay Yang waterfall tour adds the Singkhon border market, Mirror Mountain and the Waghor Aquarium and returns at 16:00. Both need swimwear and a towel.
If walking is a burden, the Hua Hin Explorer is lighter: the Khao Tao fishing village, Khao Tao Lake, Rajabhakti Park, Baan Sila Pin artist village and the Hin Lek Fai viewpoint by vehicle, lunch included. The mangrove and Khao Daeng tour adds a 1 km boardwalk and a river boat before a climb to a mountain viewpoint, so sturdy sneakers are a must.
For the evening before the countdown, look at the Cha-Am and Nayang bat caves tour: a 14:00 hotel pickup, a train to Cha-Am, and at 18:00 bats lifting off at dusk, back at 19:00. The evening session of the Siam Sea-Cret Cruise picks up at 15:00, returns at 21:00 and includes a dinner buffet.
Hua Hin has no clearly established countdown event, so check your hotel's own year-end program first and fit tours around it. Most tours here are English-guided and join tours have minimum departure numbers (four to ten guests).
Pickup times are given hotel by hotel and outlying hotels may differ in availability. What admissions and meals are included, and the rain rules, differ by product, so confirm on the current listing before booking.