Tidal swamp rice is a valuable source for developing new rice cultivars in the future because they possess some important traits for, adapted to a wide range of abiotic and biotic stresses. In this study, twenty-seven cultivars of the tidal swamp rice, comprising 26 from the South Kalimantan and one of Sumatera Island, Indonesia (an outgroup), were characterized phenotypically. Following Biodiversity International procedure, 14 qualitative and 15 quantitative traits were observed. The results show that this germplasm has a unique diversity in phenotypic traits. The secondary branch of panicle was the highest diversity of qualitative traits with an index of 0.93. Similarly, the plant height was the highest for quantitative traits (0.70). The correlation analysis confirmed that plant height, strongly correlated to culm diameter, the number of tillers and grain ratio. The PCA indicated that several independent traits, such as coleoptile anthocyanin coloration, basal leaf sheath color, and grain length, have positively contributed to the diversity, accounting 62.99%. Based on PCA analysis, the tidal swamp rice were clustered into four groups. According to UPGMA, this germplasm separated into six main groups, where Sardani (an outgroup) was very closely related to Lakatan Pacar and most distantly to Siam Perak. This information would be useful for the future rice breeding program, particularly in developing new rice cultivars in the tidal swamp areas.