The invention relates to a method for detecting leaks in swimming pools, comprising the steps of: a. Pool preparation: emptying the pool and allowing it to dry completely, b. Perforations in the bottom of the pool: making at least two perforations spaced at the bottom of the pool, c. Installing through plugs and connecting to gas tubes: placing a through-obturator in each perforation, connected by means of an elastic hose to pressurised tubes containing tracer gas (95% nitrogen, 5% hydrogen), d. Injecting and Diffusing the Gas: injecting the tracer gas through the tubes connected to the shutters. The gas will fill the space between the surface of the pool and the underlying floor. E Detecting the gas on the surface: detecting and locating the presence of the gas on the surface of the pool with a tracer gas detector and f. Identifying and marking the leaks: marking the location of the leaks and controlling the intensity of the gas flow.