Shore to finish:
Swim, Connect, Celebrate
Join our iconic open water swimming events that bring people together across the most beautiful rivers, lakes, and ocean locations in France and Switzerland.
From training to adventure
Join our open water events and turn your preparation into real open water experiences.
8 EXCITING EVENTS
Discover a wide variety of cities and landscapes in our 8 events venues in France and Switzerland.
MULTIPLE DISTANCES
Discovery, Evolution, Performance: find the distance that matches your goals.
VARIED EXPERIENCES
From ocean, to rivers, and lakes, experience swimming to the fullest.
Join the 12th OpenSwim series
The twelfth edition of the OpenSwim Harmonie Mutuelle — France’s leading open-water swimming series for the general public — will take place across eight French cities and one in Switzerland from May to September 2026.
In 20226 we launch our events in three distinguish series – Lake, River and Ocean.
Our goal is to welcome even more people into open-water swimming with events tailored to every level. The circuit also reflects our growing commitment to raising awareness about water protection, preserving our environment, and promoting the positive impact that physical activity has on health and wellbeing.
Start your challenge here
- Lake Series
- 30/05/2026 11:00 am
- Lacanau
- Crossing Lacanau Lake (3750m) - 2K - 1 K - 500m - Relay 4x500m
Lacanau
- Ocean series
- 07/06/2026 7:00 am
- Cassis
- 10K - 5K - 3,5K- 2K - 1K - 500m - Relay 4x500m
Cassis
- Ocean series
- 20/06/2026 10:00 am
- Agde
- Swimming down the Hérault (5.5K) - 3K - 1.3K - 500m
Agde
- Lake Series
- 27/06/2026 8:30 am
- Gérardmer
- Tour of Lake Gérardmer (4.5K) - 2.5K - 1K - 500m - Relay 4x500m
Gerardmer
- River series
- 11/07/2026 11:00 am
- Paris
- 5K - 2K - 1K - 500m - Relay 4x500m
Paris
- Lake Series
- 26/07/2026 7:30 am
- Prangins (Suisse)
- 5K - 2.5K - 1.25K - 500m - Family 400m - Relay 4x500m
Leman Prangins
- Ocean series
- 22/08/2026 10:00 am
- La Baule
- 5K - 2.5K - 1K - 500m - Relay 4x500m
La Baule
- River series
- 05/09/2026 2:00 pm
- Lyon
- Swimming across Lyon (7K) - 5K - 3K - 1.1K - Team challenge (1.1K)
Lyon
What our participants say
Backed by more than a decade of experience, our open water events are designed to give swimmers complete peace of mind, letting them concentrate on what matters most: the swim.
Gérardmer
A wonderful experience – thank you to the organisers. It was lovely to be able to swim around the lake.
Ka Rol
La Baule
It was so much fun
@axelreymond
Lyon
Thank you all. It was my first time swimming the 1.1km race – It was a great experience and for a good cause. I’d definitely do it again.
Séverine Sens
Lyon
Had a great time!
23_kj_79
Lyon
Pure joy
@oprah_and_tino
Paris report
A great race, very well organised – what a brilliant idea to have staggered starts rather than a mass start! It was brilliant
@lucilewoodward
Paris report
We’ll definitely be back soon! Thanks for organising it and for the race report
@joffreymaz
OpenSwim Harmonie Mutuelle Paris
A great race, very well organised – what a brilliant idea to have staggered starts rather than a mass start! It was brilliant
Get ready with our training app
Connect your watch and reach your goal
Our partners
Want to become a partner?
Swim camps
CONFIDENCE STARTS HERE
Join our Open Water Training Camps and build confidence, skills, and endurance.
