Horizen Gym
Founders
No.017
Strength training classes, personal training and open gym in Sea Point and Gardens, Cape Town
Classes are capped at 8 to 12 people so coaches can give each person attention. Strength, conditioning, mobility and Run Strong classes run from 05:30 on weekdays, with open gym and personal training alongside.
Sebastian Prentice
Sebastian Prentice, known as Seb, started Horizen with a few yoga mats, a DIY dumbbell set and some borrowed gear in Jan Marais Park. Friends came along, then friends of friends, and the early sessions were free.
When lockdown arrived in 2020, Seb began free workouts on Instagram, ran online classes and built structured coaching programmes. Once training could happen in person again, it moved outdoors to the Sea Point Promenade, driveways, gardens and garages.
Horizen became a gym in 2022 with one idea behind it: strength is a vessel, not a vanity metric. Seb also hosts Beyond Physical, the Horizen podcast, where he talks to athletes, entrepreneurs and creatives about movement, growth and building something of your own.
Horizen Gym
Horizen is a strength studio on Main Road in Sea Point, Cape Town. It grew out of free outdoor sessions in a park and is now a community of locals, digital nomads and regulars who train there week after week.
The timetable has four class types. Strength classes run in 4 to 6 week cycles with three training days a week, built around progressions and good form, and every workout can be scaled. Conditioning mixes functional movement, cardio and strength work. Mobility draws on yoga, Pilates and mobility drills. Run Strong is for runners and focuses on single-leg work and plyometrics.
Classes are capped at 8 to 12 people. The studio has a mix of functional and lifestyle training equipment, and a team of personal trainers and group-class coaches covers strength and conditioning, rehabilitation, mobility, women's strength, pre- and post-natal training and sport-specific work. Memberships include short-term flexible access, which suits people visiting Cape Town, and longer-term options. Single class drop-ins and open gym day passes are available.
A second studio at 8 Vrede Street in Gardens, next to the Company's Garden, opens in October 2026, with classes starting on 5 October.
Sea Point is open 05:30 to 21:00 on weekdays and 08:00 to 17:00 on weekends. To join, book a class or a tour through the website or the GymMaster app, call +27 66 216 7716 or email movement@horizengym.com.