H18 may refer to: Pushpalal Highway or Mid-hill Highway, a highway in mid-hilly region of Nepal British NVC community H18, a heath in the British National Vegetation Classification system , an H-class submarine ordered by but never commissioned into the Royal Navy , 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