A communication apparatus, a communication system, a communication method, and a program capable of performing relay transfer of a data file swiftly and simply in performing short-distance one-to-one communication are provided. The communication apparatus includes a communication part that performs short-distance one-to-one communication with a communication partner apparatus via electric field coupling or magnetic field coupling, a relay transfer mode setting part that sets a relay transfer mode in which a data file are relay-transferred from at least one first apparatus to at least one second apparatus, a storage part that holds the data file received from the first apparatus while the relay transfer mode is set, and a transmission control part that transmits the data file held in the storage part to the second apparatus with which communication is established while the relay transfer mode is set.