Open Around The Clock
24/7 Gym in Groton & Mystic, CT
Train on your schedule. Get unlimited 24/7 access to a serious strength and fitness facility without the crowds of a traditional commercial gym.
Starting at $45/month, or try a $15 open gym day pass.
A 24/7 Gym Built for People Who Take Training Seriously
O.N. Athletics is a privately owned 24/7 gym in Groton, CT designed for people who want more than a typical commercial gym.
Train whenever your schedule allows, use high-quality strength and conditioning equipment, and have the space to actually focus on your workout.
Whether you're an experienced lifter, an athlete, or simply looking for a better place to train, you can work out on your schedule without being tied to class times.
Inside The Gym
A Look Around The Floor
24/7 Access, Made Simple
Join O.N. Athletics and get 24/7 access through our membership app. You can schedule a tour and sign up in person, or join on your own anytime, even when the gym is unstaffed. Simply follow the instructions at the front door to complete your membership and get access in just a few minutes.
- 24/7 access through our member app
- Join in person or sign up anytime at the gym
- Simple self-service signup and access instructions at the front door
- Quick orientation before your first solo workout
Workout Anytime, With Peace of Mind
Whether you're training early in the morning, late at night, or during normal hours, O.N. Athletics is designed to make 24/7 training simple and secure.
Members access the gym through our member app, so only active members can enter. Cameras monitor the training floor and entry, and the parking area is located directly outside the gym for convenient access.
We also ask members to treat the gym like their own. Rerack your weights, keep walkways clear, and leave the space ready for the next person coming in, especially when you're training during the overnight hours.
- Controlled member access 24/7
- Cameras covering the training floor and entry
- Parking directly outside the gym
- Clear expectations for safe, respectful training
Everything You Need to Train
With 7,200 square feet of training space, O.N. Athletics gives you room to train without feeling cramped. The facility is equipped for serious strength training, conditioning, and functional fitness, with squat racks and lifting platforms, bumper plates, dumbbells, barbells, benches, plate-loaded and selectorized machines, cardio equipment, and a large open training area for sleds, sandbag carries, sprints, and other functional work.
When you're finished training, take advantage of our on-site sauna, included with your membership, without having to make another stop on the way home.
- Squat racks, lifting platforms, barbells, and bumper and calibrated plates
- Dumbbells (100lbs+), olympic benches, and accessory equipment
- Plate-loaded and selectorized strength machines
- Rowers, bikes, treadmills, and conditioning equipment
- Large open training area for sleds, carries, sprints, and functional training
- On-site sauna included with membership
- Free parking directly outside the gym
Who Trains Here At Odd Hours
Groton runs on shift work. Submarine base personnel come off watch at hours no class schedule respects. Nurses and first responders finish at 7 AM and want to lift before sleeping. Parents get an hour once the house is quiet. Early risers want the floor at 4:30 AM before the commute toward New London or Mystic.
Because those schedules spread across the whole clock, the floor is used steadily rather than all at once. Early evening is honestly our busiest window, and the late night and early morning hours are the quietest. We deliberately cap membership to help reduce overcrowding and maintain a comfortable training environment with better access to equipment and training space.
Open gym members can add coached work whenever they want it. Personal training slots and CrossFit Dýr classes sit inside the same building, so you can train solo most of the week and bring in a coach for the parts you want eyes on.
Membership, Day Passes & Parking
- 24/7 open gym: Starting at $45/month, member app access to the full floor and sauna.
- Day pass: $15 open gym day pass or $25 CrossFit class drop-in if you want to try us first, both available on our drop-in page.
- Where we are: 800 Flanders Road, Building 9 Unit 5, Mystic, CT 06355, off Flanders Road, which connects to Routes 184 and 1, minutes from downtown Mystic and a short drive from Noank, Stonington, and New London.
- Parking: free, on site, directly outside the door. No meters, no garage, no street hunting at 4 AM.
Questions about access? Call or text (860) 415-4909.
Intentionally Limited Membership
We deliberately cap membership to help reduce overcrowding and maintain a comfortable training environment with better access to equipment and training space.
Common Questions
Questions About This Program
No. Coaches and staff are on site during class and training hours. Outside those hours the gym is member-access only through our member app, with lighting and camera coverage in place throughout the space.
No. Orientation is available for new members who would like a quick walkthrough of the facility and equipment, but it isn't required before you start training.
You can schedule a tour and sign up in person, or complete your membership remotely or at the gym on your own. Once your membership is active, you can access the gym 24/7 through the member app.
If you're new to the facility or simply want someone to show you around, we're happy to walk you through the space and answer any questions before your first workout.
Absolutely. Your first visit is always free if someone wants to come check out O.N. Athletics and see if it's the right fit. Guests can complete the guest waiver at the front desk before training.
If you have a regular training partner, guest pass memberships can also be added to your membership, allowing you to bring a training partner with you whenever you work out.
And if your guest decides to become a member, you can earn cash through our referral program. We offer generous referral bonuses for members who send new people our way.
Yes. CrossFit class memberships and personal training packages both include full 24/7 open gym access, so you can train on your own whenever you want in addition to your coached sessions.
Yes. Parking is free, on site, and directly outside the door at 800 Flanders Road, Building 9 Unit 5, with no meters, garages, or street hunting at any hour.
Still Not Convinced?
We'll make it easy
Find Us
Come Visit Us
Address
800 Flanders Road, Building 9 Unit 5
Mystic, CT 06355
Serving Groton, Mystic, Noank, Stonington, New London, Ledyard, Gales Ferry & Southeastern Connecticut
Directions & Parking
Off Flanders Road, connecting to Routes 184 and 1, minutes from downtown Mystic and a short run from I-95, Noank, Stonington, New London, and Naval Submarine Base New London. Free on-site parking directly outside the door.
Get driving directionsCall or Text
(860) 415-4909Hours
Open 24 Hours7 Days a Week
24/7 member access through our member app