The disgraced glam rock singer - who had a string of chart hits in the 1970s - was jailed in 2015 for sexually abusing the girls.
The PA news agency understands the 79-year-old left HMP The Verne - a low-security category C jail in Portland, Dorset - on Friday after eight years behind bars.
He was freed automatically halfway through a fixed-term determinate sentence.
The sex offender will now be subject to licence conditions.
Glitter was at the height of his fame when he preyed on his vulnerable victims who thought no one would believe their claims over that of a celebrity.
He attacked two girls, aged 12 and 13, after inviting them backstage to his dressing room and isolating them from their mothers.
His third victim was less than 10 years old when he crept into her bed and tried to rape her in 1975.
The allegations only came to light almost 40 years later when Glitter became the first person to be arrested under Operation Yewtree - the investigation launched by the Metropolitan Police in the wake of the Jimmy Savile scandal.
Sentencing the singer, Judge Alistair McCreath said all the victims were "profoundly affected" by the abuse.
He said it was "difficult to overstate the gravity of this dreadful behaviour" when referring to the assault on one victim, telling Glitter he was able to attack another "only" because of his fame.
The court heard there was no evidence Glitter had atoned for his actions after he was found guilty of one count of attempted rape, one count of unlawful sexual intercourse with a girl under 13 and four counts of indecent assault.
He later lost a Court of Appeal challenge against his conviction.
Glitter's fall from grace occurred years earlier after he admitted possessing 4000 child pornography images and was jailed for four months in 1999.
In 2002, he was expelled from Cambodia amid reports of sex crime allegations and in March 2006 he was convicted of sexually abusing two girls, aged 10 and 11, in Vietnam and spent two-and-a-half years in jail.
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