Abstract: The present disclosure relates to a communication device, a communication method, a communication system, and a program that enable recognition of a drop of the communication device. In a communication system including an earphone and a smartphone that perform Bluetooth (registered trademark) communication, when the earphone detects a drop, the earphone notifies the smartphone of the drop and transmits a drop position notification signal for providing a notification of its own position to the smartphone by the BLE communication. When notified of the drop of the smartphone, the smartphone vibrates a vibrator to notify the user that the earphone has dropped, and specifies and displays the position of the earphone on the basis of the drop position notification signal. The present disclosure can be applied to a communication system.