A communicator was a personal handheld communications device which allowed for a person to communicate with another person over great distances.

They were mostly used by Starfleet away teams, however they were also occasionally used in situations where normal intra-ship communications were inaccessible (or inadvisable. They usually transmitted on subspace frequencies. Communicators were also often used to allow transporter locks for beaming, thus acting as homing transponders.

Communicators were in use by the United Earth Starfleet in the mid-22nd century, and used a flip top model whose basic design would remain unchanged for over a century. In the 2270s and 2280s Starfleet experimented with using a communicator which was worn on a person's wrist. However, they quickly discontinued them and returned to a flip-top design.

By the 2340s, communications technology had advanced to the point that Starfleet was able to build a communication device into the uniform insignia pin. This device, called a communicator quickly replaced communicators as a means of communication between members of Starfleet.