Near-infrared and optical and XRT X-ray light curves of GRB 100905A. In addition to the GROND detections and upper limits we also plot UKIRT J-, H- and K-band magnitudes as reported by Im et al. (2010). The XRT light curve shows some flaring activity between T₀ + 300 and T₀ + 600 s and is otherwise best fit with a single power law and a temporal decay slope of α_X ~ 0.9. The GROND and UKIRT K- and H-band light curves indicate a temporal decay slope of α_o ~ 0.6. The time intervals used to created the quasi-simultaneous broadband SED are indicated in gray.