A communication apparatus includes: a transceiver configured to receive a receive window size for use in communication with at least one communication destination communication apparatus from the at least one communication destination communication apparatus; a power-mode determining unit configured to determine a power mode to which transition is to be made, based on the receive window size received by the transceiver; a protocol stack unit configured to request the power-mode determining unit to determine the power mode at a time after transmitting and receiving data to and from the at least one communication destination communication apparatus; and a power-mode control unit configured to control electric power in accordance with the power mode determined by the power-mode determining unit.