A floating chemical dispenser is disclosed that is configured to dispense a chemical into a body of water, such as pool water. The chemical dispenser includes a float attached to a container. The container contains a chemical composition, such as a chlorine source. The container also defines an aperture that allows water to enter the container at a controlled rate. When the dispenser is placed ina body of water, water enters the container and gradually dissolves and releases the chemical. An end cap is position on the container and rotates between a closed position and at least one chemical dispensing position. The end cap further includes a locking device that locks the end cap into a closed position to prevent inadvertent release of the chemical.