Abstract: An inflatable device with a liquid-powered air pump includes a pump housing a liquid chamber and an air chamber, each having an input port and an output port. A turbine axle extends between the liquid chamber and the air chamber. The end of the turbine axle, residing in the liquid chamber, includes a number of liquid turbine blades while the end of the turbine axle, residing in the air chamber, includes a number of air turbine blades. A nozzle, which is preferably adjustable, is connected to the input port to the liquid chamber. Introduction of liquid into the liquid input port turns the liquid turbine blades and thus the air turbine blades via the axle. Air is drawn from the air input port and forced through the air output port. The pump assembly may be connected to or integrated with an inflatable device to simultaneously fill a liquid container and a separate air bladder of the inflatable device.