The Automatic Space Plasma Experiment with a Rotating Analyzer (ASPERA) measurements on board the Phobos 2 spacecraft gave, for the first time, a three-dimensional (3-D) picture of the proton flow around Mars. The measurements from the circular orbits of Phobos 2 are well suited to study the bow shock at the terminator region, the nightside magnetosheath, and the tail region. Moreover, measurements from the elliptical orbits offer dayside magnetosheath data. In this work, all circular orbits (11) where there was enough information for 3-D velocity calculations are analyzed. The solar wind deflection at the bow shock and the disappearance of the flow near the optical shadow of Mars are found to be typical features on all circular orbits. A dawn-dusk asymmetry is detected in many cases as well. When the results are compared to a gasdynamic model, the locations of the observed boundaries and the general behavior of the flow are found to be quite consistent with the model. The region where proton particle flux decreases significantly, referred to as a magnetopause near the optical shadow of Mars, was typically found near the magnetic field maximum. The magnetopause was thus inside the so-called magnetic tail boundary, which is defined to be at the broad magnetic minimum between the bow shock and the central current sheet. The magnetic tail boundary may be related to the O+ pick-up ions because the mass loading boundary also lies between the shock and the magnetopause. Because the proton flow may behave differently in the dayside than in the nightside magnetosheath, the 3-D velocities are calculated on two elliptical orbits as well. However, in these cases the nature of the flow is not possible to determine as reliably as near the terminator. ¿ American Geophysical Union 1994