Abstract: A modular shoe having interchangeable: outer shoe shell, footbed and internal heel collar. The outer shoe shell provisions a full upper secured to an outsole. The footbed provides the primary cushioning for the wearer's foot, and the internal heel collar is releasably secured to the footbed, the footbed and the internal heel collar presenting a sub-assembly that is mountable within the outer shoe shell. The modular system can include additional components such as tongue extensions and various decoratives.