A Hobart court has heard a woman was recorded having sex with a teenage boy on a camera set up to capture paranormal activity.

The 28-year-old woman from the east coast pleaded guilty in the Supreme Court in Hobart to five counts of sex with an under-aged boy between October and November 2012.

It was alleged the woman had known the boy since he was in primary school.

The boy's father discovered the sexual relationship when he was reviewing video from a camera he had set up to try and capture paranormal activity.

After being questioned by police, the court heard the boy moved to the state's west coast and the woman travelled to see him.

The pair had sex again during a six-day stay in a hotel.

The woman has been remanded in custody for sentencing next week.