Yorkshire paedophile went on holiday with 15-year-old girl after tricking family about his age
Clinton Stothard, 31, groomed the girl on the internet and tricked her into thinking he was her 19-year-old boyfriend.
Stothard, from Barnsley, South Yorkshire also targeted a number of other girls online and encouraged them to send sexually explicit photos to him.
One of his victims, a 14-year-old from Bristol, exchanged more than 3,000 calls and texts with him during a two-week period.
Sentencing Stothard at Sheffield Crown Court last week, the judge described him as "every parent's worst nightmare" and "a shark swimming in the waters of the internet...preying on children".
Stothard previously pleaded guilty to a total of 18 charges relating to 39 offences against four children.
In addition to being jailed for six years, Stothard will also be subject to an extended period on licence for 12 months and a sexual harm prevention order which will prevent him from living with any person under 18 and allowing police to monitor his internet use.
Avon and Somerset Police identified Stothard after Barnardos raised concerns about his contact with a vulnerable girl in Bristol.
Following his arrest officers examined several of his electronic devices which revealed the extent of his offending.
The investigation also led to the arrest of another man who has since been jailed for four years for child sex offences.
Owen Hall, 26, of Hartcliffe, Bristol groomed the same 14-year-old Bristol girl targeted byStothard and incited her to engage in sexual activity.
Detective Constable Kim O'Donnell, of Avon and Somerset Police, said: "ClintonStothard is a predatory paedophile who masqueraded as a 19-year-old and used a variety of aliases as he befriended and groomed his victims.
"Such was the extent of his deceit that he effectively groomed one girl's entire family - winning their trust so much they felt comfortable taking him on holiday.
"The intensity of his grooming was quite frankly shocking, with another of his victims bombarded with thousands of calls and texts over a short period of time.
"I hope the sentence handed down by the court goes some way to providing all those he preyed on with some sense of closure and that this case sends a message to those who commit such crimes, that we are committed to protecting the most vulnerable members of our society and geography will not be a barrier for us."