An isolinear tag is a dart-like device with a high-powered homing beacon utilizing isolinear circuitry attached to it.

In 2375, the Son'a tried to forcibly transport the Ba'ku from their planet, with the help of certain Federation officials. When the crew of the USS Enterprise-E put up transport inhibitors, the Son'a sent drones to fire isolinear tags to beam them up one at a time. Anij and Captain Picard were among those transported via isolinear tags. (Star Trek: Insurrection)