U43

U43 may refer to:

Naval vessels

 * GERMAN SUBMARINE U-43, various vessels
 * HMS Bideford (U43), a sloop of the Royal Navy
 * U-43-class submarine (Austria-Hungary), of the Austro-Hungarian Navy
 * SM U-43, the lead boat of the class

Other uses

 * Monticello Airport (Utah)
 * Small ditrigonal dodecicosidodecahedron
 * Small nucleolar RNA SNORD43
 * U43, a line of the Dortmund Stadtbahn