One of the most famous dive sites around Bali is Manta Point where numerous manta rays come all year round to enjoy the cleaning station. Seeing manta rays there is not always a 100% guarantee but they are there almost every day so you have a good chance of spotting them. The surrounding is very beautiful with limestone cliffs all around the bay.
Diving manta point is quite easy and shallow (max depth 15 m) and suitable for all divers. Look out also for loads of blue spotted rays on the Sandy bottom and unusually at this dive site they can be found lying on top of each other.
Divers also find octopus on the huge limestone rocks that are a feature of this dive site as well as bamboo sharks or a chance sighting of Mola Mola. This site is very popular and often crowded so try to get there early in the morning to avoid the crowd. Moreover the condition are better in the morning, after the sea could become choppy and visibility less good.