A concealable speed loader for firearms includes a flexible, one-piece body having a flat open condition, a closed annular condition, two ends and a given width. The body has grasping chambers for receiving cartridges with a length substantially greater than the given width, causing part of the length of the cartridges to protrude from the body in both the open and the closed conditions. A locking latch latches the two ends of the body in the closed condition for placement above a cylinder of a firearm with the cartridges protruding into chambers of the cylinder. The locking latch has a knob to be pulled for manually removing the body and releasing the cartridges in turn as the cylinder rotates and the cartridges drop fully into the chambers of the cylinder. A method for loading a firearm is also provided.