It's a bit further west a couple miles past the lighthouse, but Westender Inn has a very nice cove for snorkeling. There is a reef conservation project that was started by the owner some time ago and the corals and fish are abundant. The day pass is $15 usd if memory serves. There is a ladder and several nice pools, with a nice bar and restaurant on the property. The owner also culls the urchins anywhere near the ladder area, so you won't have any unpleasant surprises.