Wells in coastal aquifers can attenuate and delay aquifer hydraulic head fluctuations induced by ocean tides. To infer how the attenuation/delay depend on system dimensions and hydraulic properties, I solved a boundary value problem in which a well with storage fully penetrates a confined, coastal aquifer. The well-induced attenuation and delay are (1) maximum at the well and decrease to zero at the aquifer's horizontal periphery; (2) generally increasing functions of well radius, distance from seaward boundary, and tidal frequency; (3) decreasing functions of transmissivity; and (4) nearly independent of storativity for lesser radii and generally decreasing functions of storativity for greater radii. Approximations were developed for (1) a point in the aquifer, valid when the distance from the point to the well greatly exceeds the well radius, and (2) at the well, valid when the distance from the well to the seaward boundary greatly exceeds the radius. ¿ 2000 American Geophysical Union