"Zubian" also participated in the First Ostend Raid two months later on the night of 23–24 April. The attack was intended to close the German-held ports of Ostend and Zeebrugge, which were being used as bases for the U-boats. "Zubian" was assigned to the bombardment force, and along with the destroyers and , provided the close escort for a group of six monitors. The bombardment unit was covered by the Harwich Force in the Channel. The bombardment force was tasked with suppressing the German coastal defences, while a pair of old cruisers attempted to steam into the harbour entrances, where they would be sunk as blockships. The effort failed when both cruisers ran aground far outside of the harbour.