In this study, moisture‐permeable waterproof film materials exhibiting temperature‐sensitive hydrophilicity are investigated. The water resistance properties of copolymer films prepared by combining water‐soluble poly(N‐isopropylacrylamide) (poly‐NIPAM) with hydrophilic polyurethane (PU) are examined. Water‐soluble poly‐NIPAM is synthesized as a diol and then copolymerized with PU. Structural investigations confirm that water‐soluble poly‐NIPAM and hydrophilic PU are combined through PU links. In terms of physical properties, the films are confirmed to be water‐insoluble. Furthermore, based on the relationship between the water‐swelling ratio of the film and the water temperature, the films exhibit temperature‐sensitive hydrophilicity, with the water‐swelling ratio changing across the lower critical solution temperature (LCST). Moreover, the drying rate of the water‐absorbing film is different across the LCST. From these results, it is confirmed that a functional film with temperature‐dependent hydrophilicity is achieved. This property enables the poly‐NIPAM/PU copolymerized films to be used as moisture‐permeable waterproof fabrics for sportswear.