The parents, from Prestatyn, Wales, admitted charges of child neglect after the man raped their son during the holiday. The paedophile is now serving a life sentence for rape and other sex offences
The police and social workers had warned the family not to allow the man to go on holiday with them.
Wales Online reports that the man had also sexually abused two other children when he was allowed to visit the family home.
Mold Crown Court heard that the mum had 'done nothing' when she was told by one of the children what was happening.
Jailing the father for four years and the mother for three and a half, the judge said they had 'deliberately' put their children in 'harm's way'.
"You knew full well that you had a responsibility to protect your children from his predatory attentions," the judge said. "In particular you should not have allowed him to accompany you and the children on holiday. You let him come, you failed to look after your children, and he raped your son."
The court heard that one of the children had been abused by the man at least 30 times, and that she had tried to stop him abusing her sister by telling their mother what he had done to her. "Yet still you did nothing to protect your children," the judge said.
It was revealed in court that social services were monitoring the family at the time and had told them not to let the sex offender near the children.
The couple's children have since been taken into care.
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