Before the shooting, the actors trained for seven months, especially with Julie Fabre, former coach of the French Olympic synchronized swimming team. If the latter was initially skeptical, she told Gilles Lellouche that things would finally be able to be done after three weeks.
A competing film, Regarde les hommes nager (2018), was released in the summer of 2018 in England. Like Le Grand Bain, this feature film is inspired by the same true story of a Swedish club.
The shots of the Grand Bath take place over fourteen weeks in the Auvergne-Rhône-Alpes region and in Île-de-France. Filming begins on February 8, 2017 in the Paris region, including, in April, some shots are taken at the Raincy pool and the parking Franprix warehouse Chennevières sur Marne, and in late April, the scenes of the film are shot in several communes of the south of the Aisne, namely Grand-Rozoy, Parcy-Tigny and Château-Thierry. Subsequently, the film crew travels to Isère in Grenoble and its agglomeration, whose scenes are filmed at the Leclerc shopping center in Echirolles, at the Champ-sur-Drac gymnasium, at the Grenoble campus and in a high school in Paris. agglomeration of Grenoble. Lans-en-Vercors is part of Iséroises filming communities in March 2017.