The results of this work are based on investigations conducted over a period of four years at Tel Michal and Apollonia, and are the result of 2,300 actual underwater hours. Evidence collected from written sources and field-work brings the authors to the conclusion that the Mediterranean coastal harbour, or anchorage, at Tel Michal (on the Israeli Sharon Plain) was located in an estuary on the southern or south-eastern side of the high tell. Excavations show habitation from the Middle Bronze Age to the Persian period. Tel Michal declined during Persian rule as Apollonia (lying 3.5 km north) was founded and grew in importance. The overall objectives of the study were to determine whether the two settlements possessed their own harbours, anchorages or beaching shores, or whether their economic development was solely dependent on the hinterland and land-borne transport.