Forecasters at the island's Met Office say there will be coastal overtopping in the early hours tomorrow.
They have issued a yellow weather warning for two high tides.
The first is between 1am and 4am; the second between 1.30pm and 4.30pm.
High tides are at 2.30am and 3pm.
Areas at risk include central and northern ends of Douglas promenade, Castletown promenade, Shore Road, Rushen (Gansey) and to a lesser extent Laxey promenade and Ramsey promenade.