The Heinkel HE 8 was a reconnaissance floatplane built in Germany in the late 1920s. It was developed at the request of the Danish Navy, which had noted the success of the HE 5 in Swedish service, and wished to purchase a similar aircraft as well as licensed production as the Orlogsvaerftet HM.II. Apart from its new Armstrong Siddeley engine, the HE 8 also differed from the HE 5 and previous members of the HE 1 family in having a conventional empennage. 22 aircraft were operated until the German invasion in 1940, after which one example was impressed into Luftwaffe service and the remainder placed in storage.
A single HE 8 was built with a Packard 3A-2500 engine and designated HE 31.