Apparatus and methods for diplexing by antenna structure are provided. In certain embodiments, a mobile device includes a front end system and an antenna structure. The front end system includes a first signal conditioning circuit configured to condition a first radio frequency signal of a first frequency, and a second signal conditioning circuit configured to condition a second radio frequency signal of a second frequency that is lower than the first frequency. The antenna structure is configured to diplex the first radio frequency signal and the second radio frequency signal, and includes a first antenna configured to handle the first radio frequency signal and a second antenna electromagnetically coupled to the first antenna and configured to handle the second radio frequency signal.