In July 1917, all six ships rendezvoused off the Cocos Islands: the first time the entire class had been in one location. From there, the River-class destroyers proceeded to the Mediterranean. On arrival at Malta, they were immediately deployed as escorts for a convoy. After this, the destroyers were modified for anti-submarine warfare: the aftmost torpedo tube was removed and replaced with depth charge rails. From August 1917, the six destroyers were based at Brindisi, Italy, assigned to patrol the Adriatic and prevent enemy submarines using it as a route to the Mediterranean.