David Budd, 72, was handed an eight year and 10 month sentence at Snaresbrook Crown Court in north-east London on Thursday after admitting a string of historical offences, Metropolitan Police said.
Budd's offending took place in the Newham area of east London in the 1970s. The four female victims were all aged about nine at the time.
Scotland Yard said Budd was more recently living in Orihuela Costa in the Spanish resort of Alicante and was arrested at Southend Airport on December 21 2017 as he arrived back in the UK.
Detective Constable Colleen Ryan from the Met said: "Budd was an ice-cream seller in Newham, a position he used to gain access to and groom his victims.
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"He preyed on young children by using his position as an ice-cream seller to groom them. He succeeded in gaining their trust and then subjected them to abuse that no child should ever have to endure.
"I would like to commend them (the victims) for their bravery in coming forward and finding the courage to speak to police. We never underestimate how difficult this must be.
"Child abuse will never be tolerated. I hope this conviction sends out a strong message to people that no matter the passage of time that has passed police will conduct a thorough investigation and make every effort to bring the perpetrators of these depraved crimes to justice."
Budd admitted seven counts of indecent assault and four counts of indecency with a child.