Oyster shell-filled bags have been used in engineered reefs and living shorelines as a nature-based solution to attenuate wave energy and stabilize shorelines. However, due to limited scientific data, uncertainties persist in accurately predicting the performance of these reefs, which can hinder a more widespread adoption. In particular, there is a lack of information on wave transmission through, and the stability of, oyster shell-filled bag berms with different configurations and relative freeboards. To address this knowledge gap, a full (1:1) scale experimental flume study was conducted to measure the wave transmission and stability of six different oyster shell-filled bag berms under a range of incident wave conditions and water levels. The findings from the experimental tests were used to propose empirical equations for wave transmission and stability, which can assist practitioners in predicting the performance of these engineered reefs.