A bicycle carrier system for vehicles may include guide rails provided on a bumper back beam, a carrier device connected to the guide rails and configured to slide along the guide rails to be withdrawn from and received in the bumper back beam, a first driving device disposed on the carrier device and connected to the guide rails to move the carrier device along the guide rails, tilting devices configured to selectively connect the guide rails and the carrier device to each other and to release connection between the guide rails and the carrier device so as to tilt the carrier device from the guide rails when the carrier device is moved to a designated level or higher during withdrawal of the carrier device according to operation of the first driving device, and a communication control module.