The synthesis, X-ray diffraction, Hirshfeld, DSC, TGA-dTG, and Infrared spectrum of a new [C6H5NH3]3BiCl6·3H2O crystal are reported. The crystal structure of the title compound at 293 K [P212121; Z = 4; a = 7.4348(3)Å, b = 16.5416(6)Å, c = 22.0510(8)Å] comprises units containing an isolated and distorted BiCl63−octahedron, three independent organic cations, and three independent water molecules linked together by NH⋯Cl, NH⋯O, OH⋯Cl, and OH⋯O hydrogen bonding to form organic-inorganic network. The X-rays powder diffraction pattern is satisfactory indexed and affined on the basis of an orthorhombic unit cell, with parametrs closed to those determined by single crystal X-ray diffraction. Hirshfeld surface analysis and fingerprint plots methods are used to identify and analyze the significant intermolecular interactions in the crystal network, and to determine the contribution of the component units in the crystal structure construction. DSC curves show two non reproducible and irreversible endothermic anomalies (T1 ≅ 115 °C, T2 ≅ 132 °C), which correspond to the dehydration due to removing of water species from the crystal structure. TG-dTG analyses confirm that the removed water is of crystallization in agreement with X-Ray and DSC analyses. The study of Infrared spectrum at room temperature confirms the presence of C6H5NH3+ cations, H2O molecules, which are linked to BiCl63− anions by hydrogen bonding.