I think my favorite day in Thailand was the day we spent on the sea and sand. We took a day-long excursion among the Phi Phi islands about an hour by boat from the main port on Phuket. It was a beautiful sunny day and the tour took us snorkeling in deep blue and turquoise waters, bathing on sandy beaches, lunching over the jade-colored sea and giving bananas to beach monkeys. The monkeys were less a hit with the boys since they are a common sight in Delhi, but the sand and water were, of course, their favorites.
These big rocks were amazing and really reminded me of some parts of New Caledonia: