You have to wake up early, but if you're into dolphins it is totally worth. Lovina, in the northwest of Bali, is one of the best locations in the world to spot these special mammals. Local fishermen know exactly where the dolphins tend to swim. If you pay them a fee they will take you on a trip to see the dolphins. Since the animals are most active around dawn, you will leave early in the morning. That way you're most likely to spot them.
If you still have energy after the boat ride, go to Air Panas Banjar, a natural hot spring where you can take a nice warm bath. Only a few kilometers away you can visit Brahma Vihara Arama, the only Buddhist monastery on Bali.