The rapidly changing wind-wave pattern as a consequence of climate change can adversely affect the safety and integrity of offshore structures. This paper presents a performance-based design of a tension leg platform (TLP) in Tamil Nadu by incorporating the future climate during the power production stage. Climate projection is carried out with respect to different carbon dioxide emission scenarios ranging from SSP1-1.9 to SSP5-8.5 through statistical downscaling and the Artificial Neural Network (ANN) algorithm. A three-dimensional numerical model of tension leg platform wind turbine is developed in Abaqus CAE, where soil is modeled using API-based py, qz, and tz curves. The performance of TLP is evaluated based on the capacity factor of various responses, including acceleration at the nacelle, tower deflection, the mean displacement of the platform, mudline rotation at the anchor, and the pretension of the cable. After incorporating the future climate, the serviceability responses are increased by up to 33%, consequently reducing the safety margin. The maximum change is observed in the acceleration response at the nacelle. This study is useful for the designers to incorporate the future climate into their designs and provides a new perspective that is often overlooked in current design practices.