In this paper, a framework is developed for classifying bay types using stability and a sediment supply source. The framework is used to classify a total of 212 headland-bay beaches in Southeast Asia. The results show that static bays, bays with no sediment supply, and dynamic bays (with a sediment supply), account for 36% and 64%, respectively, while stable bays, bays that can maintain their long-term shoreline stability, and unstable bays (changing their shape over time), account for 69% and 31%, respectively. The results reveal the importance of dynamic bays. The dynamic parabolic bay shape and bay characteristic equations have been verified to bridge the knowledge gap of coastal stabilization and management in dynamic bays. The verification of bay characteristic equations shows an efficiency index of more than 78%. The bay characteristic equation shows that dynamic bays are highly sensitive to low sediment supply and become less sensitive when the sediment supply increases. Knowledge of the coastal stabilization concept successfully implemented for static unstable bays has been extended in this study and applied to stabilize dynamic unstable bays using the verified equations. Sediment control and the combined method are developed in this study, and a case study is presented on the stabilization of a dynamic unstable bay.