For El Nido Tour A, you get to either visit the Big Lagoon or the Small Lagoon but not both in one day, due to government regulations. Both are equally nice and located beside each other at Miniloc Island.
The Small Lagoon has the most peaceful, enchanting and beautiful blue-green waters that one can kayak or swim in. Kayaks are for rent at the entrance, subject to availability.
To get into the Small Lagoon, one will have to pass through a small opening on the rock face.