A magnetic snap fastener for releasably coupling a first material to a second material. The fastener includes a first fastening assembly affixable to the first material, and disposed in a first water-resistant enclosure. The fastener includes in one embodiment a second fastening assembly affixable to the second material. The first and second fastening assemblies each include a ferromagnetic eyelet having an integrally formed flange and protrusion magnetically coupled to a toroidal-shaped magnet. Alternatively, the second fastening assembly is a ferromagnetic cap or button. The first and second fastening assemblies provide magnetic coupling to releasably couple the first and second materials.