Sea Lion Encounter at Atlantis

[NewCruiser2011]

We are thinking of doing the Sea Lion Encounter at Atlantis, we will dock at 07:00 and depart at 14:00. We were looking at the Blue Lagoon one but we dock on a Sunday and I hear the beach is closed. Has anyone done the Sea Lion Encounter at Atlantis? Is it worth it?

Carnival seems to offer tons of shore excursions to Atlantis except the Sea Lion one, is it easy to book ourselves?

Thanks in advance for all your help (I am new to cruising, this will be our first)