Constructing a zero-carbon island microgrid with a water and power supply system is an effective means to promote the sustainable development of independent islands. However, energy storage aging significantly impacts its storage power and operating power over time. To improve the reliability of island microgrid planning results, a collaborative electricity-water planning method for zero-carbon microgrids on an independent island considering the dynamic aging characteristics of energy storage is proposed. Firstly, refined physical models of electrochemical energy storage and hydrogen energy storage are established to analyze aging effects on operating efficiency. Secondly, a freshwater preparation system is introduced to establish a zero-carbon microgrid electricity-water cooperative planning model for independent islands in order to minimize the total investment operation and maintenance cost of the microgrid. To enhance the model solution speed, the planning problem is divided into two layers. The upper layer optimizes the installed capacity of the energy storage system with minimum investment cost based on the capacity of renewable energy, and the lower layer replans renewable energy capacity based on the upper layer′s results. Then, the ADMM method is used to solve iteratively until the total investment cost converges to obtain the optimal island planning scheme. Finally, the simulation analysis of a Fujian island verifies the method′s rationality and effectiveness.