The Underground Spa & Wellness at The Logan Hotel

The Underground Spa & Wellness sits below The Logan Hotel at One Logan Square, pairing a treatment menu of massages, facials and body work with a small health club. The main draw beyond the spa suites is the heated indoor saltwater pool, paired with a fitness center, locker rooms and showers — there's no sauna, steam room, hot tub or cold plunge here, so plan accordingly.

Anyone booking a service gets same-day access to the pool and fitness center, plus complimentary beverages, and can arrive early or linger afterward. Hotel guests use a room key card to get into the pool and gym; spa guests check in at the spa front desk instead. Day passes are also sold separately, subject to availability, running 10:00 a.m. to 6:30 p.m. with facilities closing at 6:00 p.m. — worth calling ahead to confirm a spot.

Couples massages are available side by side in a dedicated couples suite, and the spa handles group bookings for bachelorette parties, birthdays and similar occasions, including a private Chill Vibes Room for groups to gather for an extra fee. Reservations require a 50% deposit, individual appointments need 24 hours' notice to cancel or change, and group bookings require 72 hours. The spa is open daily from 9:00 a.m. to 8:00 p.m., and services can be booked by phone at (215) 405-2815.