A detachable waterproof pocket may include front and rear surfaces made from an impermeable material and forming a receptacle having an open top portion. Interlocking elements, on the front and rear surfaces, may engage with each other to close the top portion of the receptacle with a watertight seal. A first attachment element, above the interlocking elements on one of the surfaces forming the receptacle, may engage with a complimentary second attachment element on a garment in order to attach the waterproof pocket to the garment. The interlocking elements may comprise complimentary tongues and grooves. The complimentary first and second attachment elements may comprise complimentary zipper chains of an open-ended zipper. The garment may be a swimsuit and the complimentary second attachment element may be located on an inner surface of the swimsuit. The swimsuit may include a waistband and the second attachment element may be sewn into said waistband.