The present invention comprises a system for the localized heating of a portion of water within larger water bodies through a partial confinement of said portion of water without completely intemrpting the water flow and where the concept of being in the same water body is maintained, in order to facilitate the practice of recreational activities in a heated environment. The present invention provides a solution to achieve a comfortable temperature of the water for direct contact recreational purposes in a cost-efficient manner, with a partial confinement system that allows creating a heat plug and provides for a serpentine-type flow between both sides of the partial confinement system.