H18

H18 may refer to :
 * British NVC community H18, a heath in the British National Vegetation Classification system
 * HMS H18, an H-class submarine ordered by but never commissioned into the Royal Navy
 * HMS Sabre (H18), a Royal Navy S-class destroyer
 * London Buses routes H18, a Transport for London contracted bus route
 * Sikorsky H-18, an American helicopter
 * Tomakomai Station, in Hokkaido, Japan