By utilizing inherently generated TM11 and TM02 modes of a patch antenna, a new dual-band dual-mode antenna is proposed for off-/on-body centric communication. The antenna consists of a simple probe-fed circular patch with a shorting pin and two arc-shaped slots, which are added to tune the resonances of the corresponding modes to the desired frequencies of 2.45 and 5.8 GHz. A broadside radiation pattern suitable for off-body communication and a monopole-like radiation pattern for on-body communication are thereby provided at each frequency, respectively. To determine the human body's effect on the antenna performance, a study has been conducted through simulations in both free space and on a human body-equivalent phantom. The results reveal a robust performance of the antenna against the human body loading, which indicates that the proposed antenna is a very promising candidate for body centric communications.