Yunomori Onsen and Spa

Vibe: A luxurious, zen combination of wood and black tile. The onsen tub in a private garden is the perfect place to unwind.
Price: B1,750 for a complete package that includes a day pass to the mineral-rich spring water onsen, a 90-minute aromatherapy body massage and 30 minutes of a herbal compress.
A Square, Sukhumvit Soi 26, 02-259-5778. Open daily 9am-12am. www yunomorionsen.com/bangkok
 

Kashikiri Soda Onsen and Spa

Neighborhood: Phrom Phong
Vibe: Luxurious and traditionally Japanese with private onsen wooden tubs.
Price: B3,200 for the Kashikiri Essence of Oriental signature package that includes a 30-minute private onsen, a 45-minute tropical fruit almond body scrub, a 30-minute body mask, and 60 minutes of traditional Thai massage.
84 Sukhumvit Soi 49, 081-268-4624. Open daily 9:30am-10:30pm. www.kashikirionsenandspa.com 

At Ease Massage and Spa

Vibe: Clean and polished, but with Thai accents like lai kanok prints. 
Price: B950 for the Enzyme Bath, which includes 15-20 minutes of being wrapped in hot rice bran enzymes (sand bath), good for blood circulation and melting away fatigue, plus a 30-minute cool down and shower. 
593/16 Sukhumvit Soi 33/1, 061-682-2878. Open daily 9am-midnight. www.atease-massage.com