Wave energy presents a promising avenue for renewable energy generation due to its high energy density per unit area, surpassing other sources. With the decommissioning of offshore platforms posing significant costs, repurposing these structures for wave energy development emerges as an economically viable solution. Oscillating Water Columns (OWCs) stand out as effective wave energy converters, harnessing pneumatic energy from wave motion to generate electricity via turbine rotation. However, Malaysia’s mild wave climate presents a unique challenge compared to previous OWC deployments in more energetic environments. This research endeavors to address this challenge by developing an Off-shore OWC configuration equipped with a bottom barrier, tailored for mild wave climates. Key factors influencing OWC performance, including bottom barrier shapes, submergence depth, and support system type, are thoroughly examined. Physical experiments probe the impact of the OWC column’s cylindrical geometry on the optimal bottom barrier configuration. The findings not only offer insights into enhancing Offshore OWC efficiency but also lay the groundwork for adapting OWC technology to low wave energy climates. Ultimately, this research aims to breathe new life into decommissioned offshore platforms, transforming them into sustainable wave energy devices and contributing to the global shift towards cleaner energy sources.