Lan is correct. There can be a moderate current particularly on a windy day. However, you start out against the current most of the time (wind coming into the island) so you glide back to the boat which will be in very shallow water.

My wife whose longest snorkel experience was 10 minutes (she hyper ventilated and freaks out) lasted 40 minutes there. I was diving and as soon as the boat dive master saw she was uncomfortable he was at her side.

It's the best snorkel spot I've been to in the Caribbean. Clear, great coral, perfect brain coral visible (25 feetdown maybe).