The Douro Bridges Porto & Gaia Open Water is a 4 km river swim held in September on the Douro River, taking place between Porto and Vila Nova de Gaia. Participants begin at Cais da Ribeira in Porto, approximately 200 meters from the Luís I Bridge, and swim towards the beach adjacent to Douro Marina on the Gaia side. This event is organized by the North Portugal Swimming Association, overseen by the Portuguese Swimming Federation, and is part of the National Open Water Circuit. The 4000m race contributes to the AA and Masters AA standings.
The course navigates under the Douro bridges, connecting the race directly to Porto and Gaia, unlike lake or coastal swims. Approximately 400 swimmers are anticipated, including prominent open-water athletes. Entrants for the circuit must be a minimum of 14 years old. The time limit for the 4000m distance is 1 hour and 45 minutes, with electronic timing employed. Wetsuit usage is determined by the official water temperature. Open-water swimming on the Douro was reinstated after a significant hiatus since the previous edition in 1979, marking a notable return for this series.