Understanding how ocean wave groups evolve and modulate across the continental shelf is critical for predicting coastal hazards such as erosion, resonance, and infragravity (IG) wave generation. Traditional oceanographic instruments often lack the spatial and temporal resolution needed to capture these dynamics over kilometer-scale distances. Distributed Acoustic Sensing (DAS) offers a transformative approach by repurposing existing seafloor telecommunication cables into dense, long-range sensing arrays capable of detecting nanoscale strain. DAS data will be analyzed for two field experiments: first, observations made on 1.5 km of a placed subsea cable in the nearshore of Duck, NC, and second, observations made on 20 km of a subsea fiber-optic telecommunications cable offshore Florence, Oregon. Both datasets are complemented by ground-truth observations from moorings and X-band radar or surface camera. Processes such as ocean gravity wave significant wave height, wave reflection, wave breaking, and wave group dynamics are assessed. Ocean gravity wave significant wave heights are accurate to within 80% of the ground truth measured wave height. DAS-derived group velocities generally aligned with linear wave theory, though deviations scaled inversely with group energy. Group amplitudes exhibited cross-shore modulation at ~500 m scales, with dynamic range and modulation frequency tied to wave energy. Future work will assess how DAS may be used to capture infragravity band signals. These results demonstrate DAS’s capability to resolve ocean wave dynamics, offering new insights into wave energy transfer and supporting improved forecasting of hazardous coastal conditions.