Water bottle/bladder – at least one litre or more re-useable water bottle-Nalgene, Camelback, etc.
Sunglasses with a strap
Sun-cream – essential!!
Hiking shoes – walking in and out of the beach site
Closed-toed water shoes (no Crocs, no flip-flops, no sandals – shoes must stay on your feet when wet)
Change of clothes/shoes for after the lesson
A packed lunch or money for the local restaurants