The Short N.3 Cromarty was a prototype British twin-engined biplane flying boat, designed towards the end of the First World War.

[1] This resulted in designs from Vickers (for the Valentia) and Shorts of Rochester, who, although better known at the time for floatplanes, had gained experience in flying boats, building Felixstowe F.3 and F.5s under licence from April 1917.

It was powered by two 650 hp (480 kW) Rolls-Royce Condor engines, and had a similar, but larger hull to that of the Felixstowe flying boats, with a biplane tail.

In August, the Flight, comprising the Cromarty, two Felixstowe F.5s and a Phoenix Cork, set out on trials of operating large flying boats away from support facilities for extended periods of time.

Arriving at St Mary's, Isles of Scilly on 21 August, the Cromarty successfully weathered a storm, but was taxied onto a reef, holing the hull.