Proper thermal management is important to the successful operation and durability of proton exchange membrane fuel cell (PEMFC) systems. In liquid cooled fuel cell systems, the planar temperature distribution of the cell is largely controlled by the coolant flow field (CFF) design inside bipolar plates (BPPs). We characterize the temperature distribution of the coolant in two different CFF designs made out of Ti-6Al-4V titanium alloy by using infrared (IR) thermography and a coupled heat-transfer numerical model. Numerical models show that the two CFFs have nearly equivalent global heat transfer characteristics and temperature distributions but very different coolant flow characteristics; one design has uneven flow through parallel cooling channels and the other design has even flow through parallel cooling channels. These two designs are used to probe the capability of IR thermography to resolve subtle differences in temperature distribution in the CFFs. We find that the temperature distribution in CFFs measured using IR thermography matches the predicted numerical model results. We conclude that IR thermograph is a useful tool for characterizing CFFs because it can visualize local temperature differences caused by trapped bubbles in addition to the overall in-plane temperature distribution. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.