This book is a taxonomic report on plankton algae found in samples collected in Bali, Indonesia. This book is a taxonomic report on plankton algae found in samples collected in Bali, Indonesia. A total number of 593 taxa containing 52 taxa of Cyanophyceae, 6 taxa of Chrysophyceae, 5 taxa of Xanthophyceae, 10 taxa of Dinophyceae, 223 taxa of Euglenophyceae, 297 taxa of Chlorophyceae, included rare or unique algae, has been described in this book along with photomicrographs and figure of each algae. Since many of species have a cosmopolitan nature, there is a possibility that help this book in areas outside of Bali. Actually, the author had been researching the same pond in Japan for about 20 years, there were 154 taxa same as Bali.