SS-42, SS 42 or SS42 may refer to:
BAP Abtao (SS-42), a submarine of the Peruvian Navy SS 42 the road over both the Mendelpass and the Tonale Pass in Italy USS L-3 (SS-42), a submarine of the United States Navy which saw service during World War I
See also
USS S-42 (SS-153), a submarine of the United States Navy which saw service during World War I