The availability of ten 6 inch Mk XII guns from the Queen Elizabeth-class battleships in 1915 prompted the Admiralty to order five scaled down versions of the M15-class monitors, which had been designed to use 9.2 inch guns.

HMS M32 and her sisters were ordered from Harland & Wolff, Belfast in March 1915.

She later took part in the Battle of Jaffa and remained there until March, 1919.

She served from May to September 1919 in support of British and White Russian forces in the White Sea, before returning to England.

HMS M32 was sold on 29 January 1920 for use as an oil tanker, and named Ampat.