Leon Kidner took the 15-year-old girl to a caravan in the seaside resort of Pendine, Carmarthenshire, on 13 June last year.
Swansea Crown Court heard that Kidner waited until she had fallen asleep before carrying out the attack.
Kidner, of Pendine, was charged with rape and two counts of assault by penetration.
He denied all three charges, forcing his victim to give evidence in court.
However, a jury convicted him of all three offences after hearing the evidence in the case.
Kidner appeared at Swansea Crown Court for sentencing on Tuesday 3 March, where he was jailed for ten years.
Following the sentencing, the Crown Prosecution Service said Kidner had taken advantage of the situation for his own sexual gratification.
Samantha Mainwaring of the CPS said he had used his power over the girl to intoxicate her, making her even more vulnerable to his attack.
“These convictions result from the Crown Prosecution Service presenting strong evidence to the jury, rebutting Kidner’s claim that the sexual acts were consensual,” she said.
Ms Mainwaring also praised the victim for her bravery in coming forward and supporting the prosecution.
“The victim showed courage in reporting the offences and supporting the case. Through her strength this rapist has been brought to justice,” she added.
Dyfed-Powys Police’s investigating officer, Detective Constable Katie Rees, also paid tribute to the victim’s “profound courage”.
“I would like to extend my heartfelt thanks and gratitude to the victim in this case who showed profound courage from the very outset of the investigation, despite her young age,” she said.
DC Rees said the victim had shown “immense strength, character and resilience” and should be proud of how she had conducted herself throughout the investigation.
“It is thanks to her bravery that Leon Kidner will now spend a significant period in prison,” she added.
In addition to the ten-year jail term, Kidner was also made the subject of a lifelong Sexual Harm Prevention Order.
He was also ordered to register as a sex offender for life, and a restraining order was imposed for life.
