The Latham 43 was a flying boat bomber built in France in the 1920s for service with the French Navy. It was a conventional design for its day - a two-bay biplane with unstaggered wings, and engines mounted tractor-fashion on struts in the interplane gap. The pilot sat in an open cockpit, with a gunner in an open bow position, and another in an open position amidships.
Two examples, designated Latham 42 powered by liquid-cooled Vee engines were evaluated by the navy in 1924, leading to a contract for 18 aircraft powered by air-cooled radial engines instead. Designated Latham 43 by the manufacturer and HB.3 in naval service (for Hydravion de bombardement - "Seaplane-bomber", 3 seats), they remained in service between 1926 and 1929.
Eight other machines with the original liquid-cooled engine were sold to Poland.