On the shore is the Captain Cook Monument. You can reach this place by a one hour walk along a dirt track. Bring enough water and food. It's a long walk down in the morning and a very long walk uphill after a long day of snorkeling. Less adventurous people can take a snorkeling tour boat.
Visibility is good and both coral and fish are abundant.
There was a big moray eel, and at the end of the day when almost everyone was gone a turtle passed by. During the day I swam out into the blue when I saw a huge black shadow in the water. Fortunately it was a manta ray. Another day I tried to go snorkeling halfway down the bay, but that wasn't very good. Because of a big swell it was hard to enter the water and there wasn't much to see.