The 79-year-old singer, whose real name is Paul Gadd, was freed from a prison in Dorset, in south-west England on Friday.
It is common for offenders in the UK to be freed halfway through their sentences and then be placed on probation.
“Sex offenders like Paul Gadd are closely monitored by the police and Probation Service and face some of the strictest licence conditions, including being fitted with a GPS tag,” the Ministry of Justice said in a statement.
“If the offender breaches these conditions at any point, they can go back behind bars.”
The singer was found guilty of one count of attempted rape, four counts of indecent assault and one count of sexual intercourse with a girl under the age of 13.
Glitter was arrested in October 2012 under Operation Yewtree, the national investigation launched in the wake of the child abuse scandal surrounding the late BBC entertainer Jimmy Savile.
Glitter is best known for the hit Rock & Roll (Part 2), released in 1972, but he fell into disgrace after being convicted on child abuse charges in Vietnam.