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    O.N. Athletics

    24/7 GYM • STRENGTH TRAINING • CROSSFIT

    A 24/7 Gym in Groton & Mystic, CT

    Home of CrossFit DYR

    O.N. Athletics is a 7,200+ sq. ft. 24/7 gym in Groton, CT, located on the Groton side of Mystic and serving Groton, Mystic, Ledyard, Gales Ferry and surrounding communities. Train independently with 24/7 open gym access, build strength with our extensive commercial equipment, join coach-led CrossFit DYR classes, or work one-on-one with a personal trainer.

    Try CrossFitPersonal Training

    5.0 from 205 Google reviews

    Open 24/7

    7,200 sq. ft.

    Locally owned

    Serving Groton & Mystic

    Why O.N. Athletics

    More Ways to Train. One Place to Do It.

    24/7 Access

    Train early mornings, late nights, weekends or whenever your schedule allows.

    7,200+ Sq. Ft. Facility

    A large facility with extensive strength, cardio and functional fitness equipment.

    Commercial Gym Equipment

    Free weights, barbells, machines, cables, dumbbells, kettlebells, cardio and more.

    Strength Training

    A serious equipment selection for members who want to build strength, muscle and athletic performance.

    CrossFit

    Coach-led CrossFit DYR programming for beginners through experienced athletes.

    Personal Training

    Individualized one-on-one coaching and programming.

    Intentionally Limited Membership

    Membership is deliberately capped to help reduce overcrowding and preserve access to equipment and training space.

    Rows of cardio machines and the open 24/7 training floor at O.N. Athletics in Mystic, CT

    The Facility

    7,200 Square Feet, Open Around The Clock

    7,200+ sq. ft.
    Open training floor with room to move
    Racks & platforms
    Squat racks, lifting platforms, and bumper plates
    Free weights
    Full dumbbell and barbell ranges with benches
    Machines
    Plate-loaded, selectorized, and cable machines
    Cardio
    Rowers, bikes, treadmills, and conditioning machines
    Open training area
    Sled pushes, carries, and sprint work
    Sauna
    On-site recovery after your session
    Free parking
    On-site lot, no meters, no garages
    Member app entry
    Secure member access any hour of the day

    See what open gym includes on the 24/7 gym in Groton page, or read about the strength floor.

    Don't Just Take Our Word For It

    What Our Members Say

    Real reviews from real members in Groton and Mystic

    Rojuan Henry

    Rojuan Henry

    a week ago

    It’s an amazing environment for your work out session

    Luis Bonet

    Luis Bonet

    a week ago

    I’ve been to 5 different gyms and by far this gym is the best gym I’ve been to.

    Emerson Adams

    Emerson Adams

    a week ago

    Very clean gym, great new equipment, private/exclusive location. Best gym around the area! Great owners.

    5

    ⭐ 5.0 from 205 reviews on Google

    Take The First Step

    Start Your Journey Today

    Fill out the form below and schedule your FREE intro session. A coach will reach out to get you started at Groton's premier 24/7 gym.

    What are you most interested in? *

    Takes less than 30 seconds · Join hundreds of members · Serving Groton, Mystic, Ledyard, Gales Ferry & Stonington

    Getting Started Is Easy

    Are You Ready To Level Up?

    Step 1

    Book Your Free Intro

    Fill out the form and schedule a time to come in. We'll show you around the facility, learn about your goals, and answer every question you have.

    Step 2

    Find Your Fit

    Open gym, strength training, personal training, or CrossFit Dýr classes, on their own or combined. We'll match you with the program and membership that fits your goals and your schedule.

    Step 3

    Start Training

    Pick your class times or activate 24/7 access in our member app and get to work. From day one you'll have coaching, community, and a facility built to help you succeed.

    Find the Right Way to Train

    Compare 24/7 open gym, CrossFit DYR classes, and personal training side by side.

    View Memberships & Pricing

    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 directions

    Call or Text

    (860) 415-4909

    Hours

    Open 24 Hours7 Days a Week

    24/7 member access through our member app

    Driving in from the coast? Read our Gym In Mystic page, grab a $15 day pass, or call or text (860) 415-4909.

    Common Questions

    Frequently Asked Questions

    No. Members here range from people walking into a gym for the first time to lifelong athletes. Your free intro starts with a conversation about where you are today, and we build from there.

    Yes. Members get 24/7 member app access to the full 7,200+ sq. ft. floor 24 hours a day, seven days a week, so you can train at 4 AM before a shift or at 10 PM after the kids are down.

    Squat racks, lifting platforms, bumper plates, a full dumbbell and barbell range, benches, plate-loaded, selectorized and cable machines, rowers, bikes, treadmills, open training area, and an on-site sauna.

    No. Most members train on their own or with a personal trainer. CrossFit DYR classes are here whenever you want coached group training, and you can add them later or never at all.

    We deliberately cap membership to help reduce overcrowding and maintain a comfortable training environment with better access to equipment and training space. Member schedules also spread across the whole clock, from pre-dawn lifters to overnight shift workers. Early evening is honestly our busiest window, and the quietest hours are late night and early morning.

    Yes. We deliberately cap membership to help reduce overcrowding and maintain a comfortable training environment with better access to equipment and training space.

    Yes, two ways. Your first intro session is free and includes a tour and a conversation with a coach, or you can buy a $15 open gym day pass and train on your own for a visit. Details are on the drop-in page.

    Our CrossFit DYR coaches and personal trainers all coach here full time and carry current certifications. Ask at your free intro and we will match you with the coach whose background fits your goals.

    Book a free intro, come in for a tour and a conversation about your goals, then pick the membership that matches how you want to train. You can start the same day.

    Open gym starts at $45/month, CrossFit DYR classes start at $150/month, and personal training starts at $70/session. Military, first responder, family, and student rates are available, ask at your free intro.

    Yes. Building muscle raises the amount of energy your body uses at rest, and strength work paired with conditioning and sensible nutrition is one of the most reliable ways to change body composition and keep it there.

    We are at 800 Flanders Road, Building 9 Unit 5, Mystic, CT 06355. Flanders Road runs parallel to Route 117 and connects to Routes 184 and 1, so we are minutes from downtown Mystic. Parking is free and on-site, right outside the door.

    Still Not Convinced?

    We'll make it easy

    Call or Text