HMS E18 (Lt Cdr R C Halahan) sailed from Barrow on 13 June 1915.

The following year, on 26 May 1916 she torpedoed the German destroyer V100. The destroyer bows were blown off but she survived the attack and was later reported as salvaged and repaired. Two days later, E18 was sighted by German aircraft off Memel and on 1 June she was sighted by U 30 off Steinort.

E18 struck a mine on or about 2 June and was lost with All Hands. The wreck was located in 2012.

There is a memorial dedicated to HMS E18 in the Lutheran Church of the Holy Spirit (Puha Vaimu Kirik) in Tallin, Estonia which was inaugurated in May 2010.