Consider a coastal aquifer system with an unconfined aquifer, a leaky aquifer, and an aquitard between them. An new analytical solution is developed to investigate the effects of tidal fluctuations and leakage on the groundwater head of leaky confined aquifer extending a finite distance under the sea. The tidal fluctuations in both unconfined and leaky aquifers are considered. The leakage of the offshore aquitard, which may be formed by sedimentary depositional process of the offshore...