It was used by the Italian Naval Aviation and was later flown by crews from the United States Navy.
The M.8 was similar to earlier flying boat designs from the company but introduced new rigid wing bracing (or interplane struts).
The hull was improved from earlier designs and the tail unit was similar to that developed for the M.7.
The M.8 was powered by a single Isotta-Fraschini V.4B pusher engine mounted below the upper wing.
After World War I, a number of surviving aircraft were used at seaplane flying schools for instruction.