On 22 April 1918, the British launched attacks against Zeebrugge and Ostend, with the intention of blocking the entrances to the canals linking these ports with Bruges and thus stopping U-boat operations from the Flanders ports. "Matchless" was assigned to the Ostend operation, patrolling off the port and supporting the small craft taking part in the operation. While the Zeebrugge operation partially blocked the canal locks, that at Ostend was a failure, and it was decided to repeat the Ostend operation as soon as practicable. The operation was repeated on the night of 9/10 May 1918, with "Matchless" again taking part of the operation. The operation was a failure, with the blockship failing to block the main shipping channel. On the night of 28/29 September 1918, "Matchless" took part in a bombardment of German positions on the Belgian coast in support of the advance of Allied ground forces. "Matchless" remained part of the Dover patrol at the end of the war.