Fiber optic sensors were applied to vibration and strain monitoring of ship structures. Fiberoptic LDV sensor was used to monitor vibration at a bow of a ship in the field tests and its response to random vibration of CFRP plate on which fiber-optic LDV sensor was bonded was investigated in the laboratory. Fiber-optic LDV sensor could detect vibration of CFRP plate accurately and monitor an impact of the ship due to slamming. Fiber Bragg Grating sensor (FBG) was used to monitor strain at an upper deck of the ship in the field tests and to measure strain of a tensile specimen in the laboratory. Strain of the tensile specimen was well measured by FBG and strain of the ship which was running was monitored by FBG successfully. Tensile strength and durability of fiber optic sensor bonded on a steel specimen were confirmed in tensile tests and fatigue tests with fiber-optic LDV sensor. Structural integrity assessment with FBG was carried out using rainflow counting methods and thermal compensation of FBG was needed to monitor the structural integrity precisely.