Female musicians from the northern islands of Vanuatu use the water surface as an instrument to create a variety of unique sounds. Water music is typically made by a line of performers standing side by side, waist deep in clear island waters. Accompanied by singing, the women work in unison, exhibiting several percussive techniques, which include striking the water surface and throwing handfuls of water which scatter into droplets before impacting the surface. Each interaction produces a unique acoustic response corresponding to the air-water-hand interaction. We highlight the connection between water interaction, cavity shape and the resulting sound which was discovered by these people through their own experimentation.