A waterproof enclosure for a cochlear implant system or other hearing assistance device includes an outer housing, an inner support in the interior of the outer housing, an acoustic element supported by the inner support, and water-impermeable polymeric protective membrane sealing the interior of the outer housing against water ingress. A hearing device such as a cochlear implant sound processor, a headpiece, an earhook, or a hearing aid comprises an outer housing, an inner support in the interior of the outer housing, a microphone supported by the inner support, and a water-impermeable polymeric protective membrane sealing the interior of the outer housing against water ingress. A method for waterproofing an acoustic element comprises molding an outer support having a water-impermeable polymeric protective membrane； inserting an acoustic element into an inner support； anchoring the acoustic element to the inner support； inserting the inner support into the outer support； and anchoring the inner support to the outer support.
