The article of record as published may be found at https://doi.org/10.1121/1.403301A recursive ray acoustics (RRA) algorithm for three‐dimensional sound‐speed profiles is presented. The RRA algorithm is simple, fast, and accurate and uses arc length as the independent variable. It can be used to compute the position, angles of propagation, travel time, and path length along a ray path. The accuracy of the RRA algorithm was tested by comparing its results with those obtained from a ray acoustics algorithm that requires the solution of a system of four, first‐order, ordinary differential equations (ODEs). The ODE algorithm, which uses horizontal range as the independent variable, can only handle one‐dimensional, depth‐dependent, sound‐speed profiles (SSPs). Therefore, five standard, depth‐dependent, SSPs were used to test the two algorithms. The results from the ODE algorithm were treated as the benchmark, with respect to accuracy, for comparison purposes. The RRA algorithm proved to be very accurate for the test cases tried. After the accuracy of the RRA algorithm was validated by using one‐dimensional SSPs, its three‐dimensional sound‐speed capability was also tested.Work supported by DARPA and the Naval Postgraduate School Direct Funded Research Program, sponsored by ONR, Code 1125 OAWork supported by DARPA and the Naval Postgraduate School Direct Funded Research Program, sponsored by ONR, Code 1125 O
