S59

S59 may refer to:
 * S59 (Long Island bus)
 * S59 (New York City bus), serving Staten Island
 * Dharawal language
 * HMAS Otway (S 59), a submarine of the Royal Australian Navy
 * INS Sindhuratna (S59), a submarine of the Indian Navy
 * S59: Refer to manufacturer/supplier for information on recovery/recycling, a safety phrase
 * Savoia-Marchetti S.59, an Italian flying boat
 * SIA Engineering Company, a Singaporean aerospace company
 * Sikorsky S-59, an prototype American helicopter