Underground Fitness gives Stamford its only 20,000 sq ft, 24/7/365 fitness facility — with premium amenities at prices that don't require a premium income.
Recognized as the top gym in Fairfield County 13 years in a row — a record built on real member results, not marketing spend.
20,000 square feet of premium training space, open every hour of every day — the biggest 24-hour facility in the state.
Every premium service and amenity of a high-end chain, offered at a price point designed for real people with real budgets.
Your fitness routine doesn't take holidays — neither do we. Full access 24/7/365, no exceptions.
The equipment and amenities of a major chain. The atmosphere and personal feel of a gym that actually knows your name.
Complimentary tanning salon access comes standard with membership — no upselling, no extra fees.
Every perk of a big-chain gym — in a private setting that actually treats you like a person.
Train at 3am, noon, or on Thanksgiving — Underground is open 24 hours a day, 7 days a week, every holiday of the year.
At 20,000 sq ft, Underground is the biggest 24-hour gym in the state — you'll never wait for a machine or fight for floor space.
Every piece of equipment is chosen to deliver a serious training experience — the kind you'd expect from a high-end chain.
Certified trainers work one-on-one with you to build a program around your body, your goals, and your timeline.
High-energy group classes that push you further than you'd go alone — led by coaches who know how to motivate every level.
Members enjoy complimentary tanning salon access — the kind of perk usually reserved for gyms that cost twice as much.
13 consecutive years as the top gym in Fairfield County — a track record earned one member at a time.
Every luxury of a major fitness chain at a price point that makes staying consistent easy. No sticker shock. No compromises.
Work with dedicated trainers who design results-focused programs around your specific goals, fitness level, and lifestyle.
Community energy that makes showing up the easy part.
Full access to all 20,000 sq ft, any hour of the day or night.
Included with membership — no added fees.
Cardio, free weights, machines, and functional zones under one roof.
Underground Fitness was built on a simple but radical idea: that serious gym-goers in Stamford shouldn't have to choose between quality and affordability. The result is Connecticut's largest 24-hour facility — 20,000 square feet of premium equipment, professional training services, and amenities that rival any major chain, located at 473 Hope St in the heart of Stamford.
What separates Underground from the big-box gyms isn't just size or hours — it's atmosphere. This is a private gym that actually feels like yours. No corporate crowds, no assembly-line membership experience. Just a well-run, well-equipped space where members are known by name and results are taken seriously.
Rated the #1 Gym in Fairfield County 13 years in a row, Underground's reputation isn't built on marketing — it's built on members who keep coming back and results that speak for themselves.
Official Recognition
Reach out by phone or stop by 473 Hope St in Stamford to speak with a membership advisor and get a real look at the facility.
Select the membership option that fits your goals and budget — with access to all amenities, classes, and the full 20,000 sq ft floor included.
Walk out with full 24/7 member access from day one. No waiting periods, no orientation queues — just start training.
Use the open floor, book a class, or connect with a personal trainer. Underground adapts to how you train best.
Underground Fitness is open 24 hours a day, 7 days a week, including all holidays. Your membership never hits a closed door.
Our flagship location at 473 Hope St in Stamford is 20,000 square feet — making it the largest 24-hour gym in Connecticut.
Yes. Our certified personal trainers work with members on an individual basis to build customized programs. Ask at the front desk or call us to get matched with a trainer.
We offer a rotating schedule of Group X fitness classes covering a range of formats and intensity levels. Class schedules are available at the front desk and through our membership team.
Yes — free tanning salon access is a standard membership benefit at Underground Fitness. No hidden fees or add-ons required.
Underground delivers the same level of equipment and amenities as major chains, but in a private gym environment where the experience is more personal and the atmosphere is more focused.
You can join by calling us at (203) 569-3640, emailing undergroundfitct@aol.com, or stopping by 473 Hope St in Stamford. We also have an online membership form available.
Underground has earned its #1 ranking in Fairfield County 13 consecutive years through consistent quality, real member results, and a facility experience that doesn't cut corners.
Inside the Facility
Connecticut's largest 24-hour gym is waiting. 20,000 sq ft. Every amenity. Every hour. At a price that makes showing up easy.