An optical fiber includes a glass fiber and a coating resin covering an outer periphery of the glass fiber. The glass fiber includes a core and a cladding. An outer diameter of the glass fiber is 99 μm or larger and 101 μm or smaller. The coating resin includes a cured material of an ultraviolet curing resin composition. An outer diameter of the coating resin is 160 μm or larger and 170 μm or smaller. A mode field diameter for light having a wavelength of 1310 nm is 7.2 μm or larger and 8.2 μm or smaller. Bending loss at a wavelength of 1550 nm when wound in a ring shape having a radius of 10 mm is 0.1 dB/turn or less. Bending loss at the wavelength of 1550 nm when wound in the ring shape having the radius of 7.5 mm is 0.5 dB/turn or less.