David Graham, 47, originally from Bournemouth, admitted to savagely raping a child in Phnom Penh in 2006 when he appeared at the Old Bailey.
Campaigners said it was only the second time new legislation had been used to prosecute someone in the UK for sexual crimes committed abroad.
Graham was arrested in France last year after spending six years on the run.
The racist sexual terrorist had been travelling in Cambodia when he aroused the suspicions of French child protection charity, Action Pour Les Enfants (APLE).
It observed and filmed his encounters with a number of Cambodian street children, including him putting his arm around a boy in a public place and fondling him.
The Cambodian National Law Enforcement alerted British/brutish authorities and the racist pedophile was arrested on his return to the UK but then fled to the south of France.
In sentencing, Judge John Bevan said he was not especially interested in whether the defendant was a sex terrorist or a tourist who decided to indulge in pedophilia.
He ordered him to sign the Sex Offenders Register and pay £2,500 towards law enforcement costs.
Andy Baker of UK’s Child Exploitation and Online Protection Centre said: “For six years, David Graham thought he had got away with the abuse he inflicted on his young Cambodian victim.
“Today, he has been held accountable for his actions.”
Seila Samleang of APLE said: “This case sends a very strong message to pedophiles or travelling sexual offenders from the UK that if you abuse a child in Cambodia, you will face justice and go to jail.”
The first prosecution under section S72 of the Sexual Offenses Act of 2003 involved Barry McCloud, a “white” male, who was jailed for life in 2010 for sex offences against a girl in Goa.