There is a lot to do on the island. Here are listed some activities and attractions available:
There are a lot of places that offer snorkeling gears and trips around the island. However I think the best way to explore underwater world is to hire a boat and snorkel around the west shore near the sunset beach. On the island there are 2 certified PADI dive masters available if you would like to go diving.
If you like adrenaline activities, maybe you can try to jump off the Jembatan Cinta bridge. This could be exciting fun even for young visitors.
Nice place to relax during the day or just enjoy wonderful sunset view at the evening.
There are some nice spots around the island from shore fishing, however the best experience is to go fishing on open sea. September till late November is season for tuna and jack fish, however, there is plenty of fish during the year. Experienced fishermen can take you to night fishing as well. Please note that the sea can get bit rough during the months of December till March.
Dolphins are common around the island and you can have really close up experience. There are no tourist boats around and it will be only you and the dolphins swimming along the boat and showing off their jumps.
Learn to surf in Kuta Beach, Bali. The best choice for those ho have never surfed before.