The Mirror reports Terry had a tracking device planted under his car, a court was told.
The bug was discovered when officers searched his vehicle amid worries that he was constantly being followed by paparazzi photographers.
His lawyer, Nick "Mr Loophole" Freeman, said his client was "shocked and concerned", adding that he now knew how paparazzi found him at two events, which until then had been "a mystery".
Freeman told magistrates of the device during his appearance for speeding. He said Terry was caught as he sped away from two photographers on motorbikes.
Chelsea skipper Terry, 30, was banned from driving and fined in his absence after he admitted driving at 77mph on a 50mph stretch of the A3 near Hook, Surrey, last year.
His lawyer told the court in Staines, Surrey, that his client - along with another unnamed person - was the UK's "No 1 paparazzi target".