Tantalate semiconductors are potential photocatalysts for hydrogen generation via photocatalytic water splitting reaction because the conduction band of tantalates is composed of the tantalum 5d orbital, which is located at a more negative potential than that of the H+/H2 half reaction, i.e., 0.0 V vs. NHE. Bi3TaO7 is a stable tantalate under acidic or alkaline conditions, with a band gap suitable for visible light absorption. However, the photocatalytic properties of Bi3TaO7 are only reported based on the dye degradation reactions, probably due to the fast electron/hole recombination losses. 2D crystal-like nanosheets with a thickness of a few nanometers show unique features such as high carrier mobility, the quantum Hall effect, high specific surface area, and excellent electrical/thermal conductivity. 2D structures can also enhance the photocatalytic properties because photo-generated charge carriers in nanosheets are less prone to fast recombinations as compared to their bulk counterparts. In this study, nanosheets of Bi3TaO7 are produced by a liquid exfoliation method and the photocatalytic hydrogen generation reaction is investigated for both the as-synthesized Bi3TaO7 nanoparticles and Bi3TaO7 nanosheets.