A radio communication system comprising: a first base station that is configured to operate a first cell; a second base station that is configured to operate a second cell; a third base station that is configured to operate a third cell; a core network including a mobility management apparatus and a data transfer apparatus; and a mobile station, wherein the first base station is configured to establish a first signaling bearer with the mobility management apparatus, establish a second signaling bearer with the second base station, and establish a signaling radio bearer with the mobile station in the first cell, the second base station is configured to establish the second signaling bearer with the first base station, establish a data bearer with the data transfer apparatus, and establish a data radio bearer with the mobile station in the second cell, the first base station is further configured to send, to the second base station via the second signaling bearer, first configuration information that is necessary to establish the data bearer and the data radio bearer in the second base station, and the first base station is further configured to send, to the third base station, a HANDOVER REQUEST message including second configuration information regarding the data bearer established in the second base station when the mobile station moves from the first cell to the third cell, wherein the first configuration information includes an identifier of a user plane path regarding the data bearer to be established by the second base station, an endpoint identifier of the data bearer on the data transfer apparatus side, and an address of the data transfer apparatus, and the second configuration information includes the identifier of the user plane path, the endpoint identifier of the data bearer on the data transfer apparatus side, and the address of the data transfer apparatus. a first base station that is configured to operate a first cell; a second base station that is configured to operate a second cell; a third base station that is configured to operate a third cell; a core network including a mobility management apparatus and a data transfer apparatus; and a mobile station, wherein the first base station is configured to establish a first signaling bearer with the mobility management apparatus, establish a second signaling bearer with the second base station, and establish a signaling radio bearer with the mobile station in the first cell, the second base station is configured to establish the second signaling bearer with the first base station, establish a data bearer with the data transfer apparatus, and establish a data radio bearer with the mobile station in the second cell, the first base station is further configured to send, to the second base station via the second signaling bearer, first configuration information that is necessary to establish the data bearer and the data radio bearer in the second base station, and the first base station is further configured to send, to the third base station, a HANDOVER REQUEST message including second configuration information regarding the data bearer established in the second base station when the mobile station moves from the first cell to the third cell, wherein the first configuration information includes an identifier of a user plane path regarding the data bearer to be established by the second base station, an endpoint identifier of the data bearer on the data transfer apparatus side, and an address of the data transfer apparatus, and the second configuration information includes the identifier of the user plane path, the endpoint identifier of the data bearer on the data transfer apparatus side, and the address of the data transfer apparatus.