A Bed & Breakfast owner in Scarborough used secret peepholes to spy on his guests and make audio recordings of their most intimate moments.
At least three young couples were watched by Paul Williams, 59, from holes that he had drilled in the doors of the rooms.
He was discovered when one of his victims, a 16-year-old student, spotted a poster placed over one of the holes begin to move.
Her boyfriend investigated and found a hole that provided a view directly on to the bed. After hearing footsteps he opened the door to find Williams in a dressing gown shuffling down the corridor.
The three couples were all friends and when the others were told, they found similar hidden spy-holes in their rooms.
As the guests had been drinking and could not drive, they stayed at the guest house but moved to one room. The next morning they obtained a refund and called the police.
Audio recording equipment was then discovered in an adjoining room at the Sandsea Guest House in Scarborough, North Yorkshire.
Steve Ovenden, prosecuting at Scarborough Magistrates' Court, told the Daily Mail: 'When played, the recording sounded like people having sexual intercourse.'
Williams was arrested and admitted drilling the holes, claiming that he had made them to check residents did not leave without paying and because he suspected some of taking drugs.
But he later pleaded guilty to charges of voyeurism and observing a private act for his own sexual gratification.
He will be sentenced next month.
Hotels could offer virtual sex by 2030