A radiation imaging system includes a data processing apparatus and a radiation imaging apparatus. The radiation imaging apparatus includes a plurality of antennas for transmitting and receiving data to and from the data processing apparatus via wireless communication. The data processing apparatus transmits, to the radiation imaging apparatus, information about an antenna that is preset as an antenna to be used from among the plurality of antennas. The radiation imaging apparatus selects, based on the information, the antenna to be used from the plurality of antennas.