Abstract Much CCS research has focused on the injection interval (storage reservoir) and the immediately overlying primary seal. Considerations related to potential long-term leakage have turned attention toward the geologic overburden between the primary seal and shallow intervals containing protected groundwater. Typically the overburden interval is poorly imaged in commercially available seismic data given acquisition and processing optimized for deeper reservoir systems. Recent advances in high-resolution 3D (HR3D) seismic imaging have allowed for more thorough investigation of this critical interval in marine settings, and are well-suited for evaluating potential leakage pathways for prospective CCS sites. HR3D datasets can serve to reduce risks prior to project development as well as provide containment assurance via staggered time-lapse surveys. HR3D is likely to become a fundamental technology in offshore CCS.