The ex-Dover MP was jailed for two years in September 2020 after he was found guilty of three counts of sexual assault following a month-long trial.
The Ministry of Justice confirmed on Thursday he had been freed on Tuesday.
It is understood the 50-year-old former lawyer was serving the final part of his sentence at HMP Leyhill in Gloucestershire.
Six months ago, Elphicke lost an appeal against his jail term after his lawyers argued the sentence was too long and should have been suspended.
He was described by the sentencing judge as a “sexual predator” who used his “success and respectability as a cover” and told a “pack of lies”.
Elphicke, 49, the former Dover MP, was convicted in July 2020 of groping women, and jailed in September 2020.
He was found guilty of one count of sexual assault in 2007 and two further counts in 2016.
The Ministry of Justice confirmed his release, which a national newspaper reported was from Leyhill open prison on Tuesday.
During his trial, the jury was told Elphicke groped a woman in his home before chanting “I’m a naughty Tory”.
One assault involved a woman in her 30s, the other was a Parliamentary worker in her 20s, Southwark Crown Court was told.
His trial heard how he asked one of his victims about sex and bondage, then kissed and groped her breast before chasing her around his home saying: “I’m a naughty Tory.”
Following his appeal, his wife of 25-years Natalie Elphicke, who split from him after his conviction, divorced him.
She was voted in as his replacement MP in 2019 after he stood down, and following the case, she was one of five Conservatives who were found to have breached the code of conduct over an “egregious” attempt to influence the legal proceedings.
Mrs Elphicke, Sir Roger Gale and Theresa Villiers were suspended from the House of Commons for a day.
The three MPs, along with Bob Stewart and Adam Holloway, had written to senior judiciary members raising concerns a more junior judge was considering publishing character references provided for Mr Elphicke during the trial.
Elphicke was a government whip under David Cameron and returned to the backbenches when Theresa May became prime minister in 2016.
He had the party whip suspended in 2017 after the sexual assault allegations first emerged and it was controversially reinstated a year later as Mrs May faced a confidence vote.
When the Crown Prosecution Service announced it was charging Elphicke, the whip was removed again.