Cell migration is an important cell physiological process, which is controlled by regulated ion channel activity. It was revealed that potassium channels, in particular calcium-activated potassium channels (KCa 3.1), are required for optimal cell migration. In order to study the dynamics of individual channel proteins in the plasma membrane under physiological conditions we tracked single channel proteins during migration. Previously, we identified single KCa 3.1 channel proteins in the plasma membrane by means of quantum dot (QD) labeling (Nechyporuk- Zloy et al., AJP. 291:C266-9., 2006). In migrating MDCK-F cells the single QD-labeled channels were visualised and tracked using time lapse total internal reflection fluorescence microscopy. The main type of motion was subdiffusion with mean diffusion coefficient 0.0553 ± 0.0072 mm 2/s and subdiffusion exponent 0.88 ± 0.05. We detected no preferred direction for the movement of KCa 3.1 channels in the plasma membrane. Ion channel proteins had lower diffusion coefficients and smaller subdiffusion exponents at the rear part of the lamellipodium and at the uropod than in other parts of the cell. We suggest that subdiffusion is the main dynamical process for the transport of the KCa 3.1 channels in the membrane. The trajectories of individual QDs indicate that a combination of trapping and movement phases may be the origin of the subdiffusive behaviour.