An inflatable stand-up paddle board comprising: a body (200a, 200b, 200c, 200d) comprising: a plurality of outer sheets (202a, 203a, 206a), and an inner sheet having an upper periphery connected to one of the plurality of outer sheets and a lower periphery connected to another one of the plurality of outer sheets, such that the plurality of outer sheets and the inner sheet define an inflatable chamber therein, and the inner sheet defines an installation space separated from the inflatable chamber by the inner sheet; and an air pump (300a, 300b, 300c, 300d) disposed in the installation space, the air pump comprising: a casing comprising a box (314a, 314b, 314c, 314d) and a top cover (316a, 316b, 316c, 316d) detachably sealed to the box, and an air pump assembly (302a, 302b, 302c, 302d) disposed in the casing, the air pump assembly comprising: an air inlet (306a, 306b, 306c, 306d) in communication with an outside of the air pump assembly; and an air outlet (308a, 308b, 308c, 308d) in communication with the inflatable chamber via a first vent hole (210a, 210b, 210c, 210) in the inner sheet wherein the air pump is fastened to and removable from the installation space of the stand-up paddle board body according to its use. a body (200a, 200b, 200c, 200d) comprising: a plurality of outer sheets (202a, 203a, 206a), and an inner sheet having an upper periphery connected to one of the plurality of outer sheets and a lower periphery connected to another one of the plurality of outer sheets, such that the plurality of outer sheets and the inner sheet define an inflatable chamber therein, and the inner sheet defines an installation space separated from the inflatable chamber by the inner sheet; and a plurality of outer sheets (202a, 203a, 206a), and an inner sheet having an upper periphery connected to one of the plurality of outer sheets and a lower periphery connected to another one of the plurality of outer sheets, such that the plurality of outer sheets and the inner sheet define an inflatable chamber therein, and the inner sheet defines an installation space separated from the inflatable chamber by the inner sheet; and an air pump (300a, 300b, 300c, 300d) disposed in the installation space, the air pump comprising: a casing comprising a box (314a, 314b, 314c, 314d) and a top cover (316a, 316b, 316c, 316d) detachably sealed to the box, and an air pump assembly (302a, 302b, 302c, 302d) disposed in the casing, the air pump assembly comprising: an air inlet (306a, 306b, 306c, 306d) in communication with an outside of the air pump assembly; and an air outlet (308a, 308b, 308c, 308d) in communication with the inflatable chamber via a first vent hole (210a, 210b, 210c, 210) in the inner sheet a casing comprising a box (314a, 314b, 314c, 314d) and a top cover (316a, 316b, 316c, 316d) detachably sealed to the box, and an air pump assembly (302a, 302b, 302c, 302d) disposed in the casing, the air pump assembly comprising: an air inlet (306a, 306b, 306c, 306d) in communication with an outside of the air pump assembly; and an air outlet (308a, 308b, 308c, 308d) in communication with the inflatable an air inlet (306a, 306b, 306c, 306d) in communication with an outside of the air pump assembly; and an air outlet (308a, 308b, 308c, 308d) in communication with the inflatable chamber via a first vent hole (210a, 210b, 210c, 210) in the inner sheet wherein the air pump is fastened to and removable from the installation space of the stand-up paddle board body according to its use.