Abstract. Seawater intrusion in island aquifers was considered analytically, specifically for annulus segment (ASAs), i.e., that (in plan) have the shape of an segment. Based on Ghijben–Herzberg and hillslope-storage Boussinesq equations, analytical solutions were derived steady-state seawater ASAs, with a focus freshwater–seawater interface its corresponding watertable elevation. Predictions c...