P42

P-42 or P42 may refer to:

Vessels

 * ARA Rosales, a corvette of the Argentine Navy
 * HMS Unbroken (P42), a submarine of the Royal Navy
 * LÉ Ciara (P42), a patrol vessel of the Irish Naval Service
 * SPANISH PATROL VESSEL Rayo

Other uses

 * Curtiss XP-42, an American experimental fighter aircraft
 * GE P42, a diesel locomotive
 * Lake City Air Force Station, a closed United States Air Force radar station in Tennessee
 * MAPK1, p42 mitogen-activated protein kinase
 * Papyrus 42, a biblical manuscript
 * Phosphorus-42, an isotope of phosphorus
 * P42, a Latvian state regional road
 * P-42, a specially redesigned record-setting Sukhoi Su-27 Soviet fighter aircraft