The blue glow in the sea water is called bioluminescence. It is usually caused by an algae bloom of plankton. It glows mostly when disturbed, for example by wave breaking or a splash in the water.
Bioluminescent plankton often appears in warm coastal waters. You can see it in Australia, Japan, India, South East Asia region, African coasts, Caribbean area, US coasts in California or Florida, but also in Europe in Ireland, UK and sometimes in Mediterranean sea.