This paper investigates the capacity of multiple-input multiple-output (MIMO) antenna arrays in different on-body area network channels. The two belt-head and belt-chest channels are compared, where, belt, refers to the transmitter’s location, while the second part refers to the receiver location. The on-body channel model is constructed by using the Rice factor, the path loss, the shadowing deviation as well as the correlation matrice extracted from an intensive measurement campaign in the 2.45 GHz band. Unlike the conventional wireless models, different pathloss and Ricean factor values are evaluated and assigned for each spatial on-body subchannel in order to characterize the different statistical properties noted in the subchannels. This results in a good agreement with the measured channel. Furthermore, the maximum achievable capacity is investigated with the classic uniform power and the waterfilling schemes. It is shown that at the low SNR range, the waterfilling scheme yields a higher capacity performance, whilst similar performance is achieved with both schemes at high SNR values.