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, an inner cladding, a trench, and an outer cladding. An outer diameter of the glass fiber is 99 μm or larger and 101 μm or smaller. 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.