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To explore the influence of drifts on ion flows in the DIII-D divertor and Scrape-Off-Layer (SOL), a calibrated Coherence Imaging System (CIS) views the lower divertor. A new tuneable calibration laser and precision wavemeter provide the rest wavelength for CIII 465 nm plasma emissions resulting in  ≤  1 km/s uncertainty in ion velocities that are in the range of 30 km/s in the divertor plasma. The 2-D line-integrated velocity images have been tomographically inverted to obtain maps of ion velocity. Both He+ and C2+ ion velocity maps were measured in both directions of the toroidal magnetic field BT, and C2+ images were obtained in attached and detached L- and H-mode plasmas. The measured C2+ velocities are in the range of 20–30 km/s and are compared with UEDGE modeling with full drifts. While He II as a main ion is expected to be entrained in the plasma flow, the C2+ impurity flow involves the competition between the frictional and ion temperature gradient forces. Both the CIS data and UEDGE modeling agree that the C2+ flow is towards the divertor plates, but flips with the direction of BT. In general, the experimental C2+ emission and flow profiles have a wider spatial extent than the UEDGE modeling. Keywords: Coherence imaging, DIII-D tokamak, Divertor and scrape off layer, Ion flow