This dataset includes a list of all harmful algal bloom (HAB) reports in Indian waters from 1849 through October 2022. The authors have curated and prepared this document by scouring through historical records, which to the best of our knowledge, represents the most complete compilation to date. Important Notes: These records do not include freshwater HAB reports (e.g., from lakes, reservoirs or temple ponds), but only document marine and estuarine HABs. The authors have only compiled these reports from various peer-reviewed (or other) publications available from prior literature; they make no claim on the authenticity of these reports. Note that these records span nearly 175 years of documented observations; species names might have changed. Where possible, the authors have also provided current names of species referred to with older nomenclature in their original publications.