Big Foot Industries 
A one-stop shop for all the bare essentials of surfing and possibly the only physical store here that sells actual surfboards.

Quiksilver
This giant flagship store offers a tremendous range of clothing and accessories to get you in the mood.

Surfshop@WaveHouse Sentosa 
Can at least help you look like a surfer with a generous range of fashion wear to choose from. Also, last minute rashguards are available here just before you enter the wave check-in area.