The man, a British national, was identified by a police source as Kenneth Wright.
Officers found him at the Calahonda resort in the southern Costa del Sol, which is popular with British tourists, police said in a statement.
He initially gave a false name, police said.
The man, a registered sex offender in Britain, failed to comply with his bail terms and fled his home country on March 12th after being convicted of abusing a child over a period of seven years, Spanish police said.
Kenneth Wright is from Holton-le-Clay in Lincolnshire, BBC reported on Friday.
He was convicted in March at Nottingham Crown Court. After an adjournment for sentencing, Wright was released on bail.
He then fled to Spain at which point Lincolnshire Police issued an arrest warrant for him.
Extradition proceedings are now under way. Wright will return to the UK to serve the eight-year prison sentence he was handed in his absence, BBC reported.