The present study aimed to contribute to the algal flora of Türkiye by Bacillariophyta (diatom) as new records for the Turkish freshwater. Phytobenthos and phytoplankton were sampled three times (spring, summer, and autumn) a year between 2017 and 2019. Samples of the phytoplankton were collected with a water sampler from three depths, and samples of diatoms were obtained as epiphytic in the littoral zone of the lakes. However, if macrophytes were absent, epilithic or epipelic diatoms were sampled in lakes. Also, samples of phytobenthos were preferred as epilithic in rivers. However, if stones were absent, epiphytic or epipelic diatoms were sampled. During the studied period, a total of 895 diatom taxa were determined as planktonic (378 taxa) and benthic (860 taxa) in lakes and rivers of 25 river basins of Türkiye, and a total of 39 new records were identified. The highest diatom taxa were determined in the Fırat-Dicle, Konya, Antalya, and Büyük Menderes basins with 11, 11, 10, and 6 taxa, respectively. On the other hand, new records were not detected in 10 basins.