Example implementations relating to a modular radio frequency identification (RFID) device are described. For example, the modular RFID device includes a modular circuit pad and a modular transmission pad coupled to the modular circuit pad. The modular circuit pad includes a processing circuit to process data and the processing circuit includes multiple circuit electrical contacts. Further, the modular transmission pad includes a transmission circuit to transmit the data. The transmission circuit includes multiple transmission electrical contacts detachably connected to the multiple circuit electric contacts.