The three-time Wimbledon champion and former world number one was jailed for two-and-a-half years in April for hiding £2.5million of assets and loans to avoid paying his debts.
Becker was declared bankrupt on June 21, 2017 - owing creditors almost £50m - over an unpaid loan of more than £3m on his estate in Majorca.
The 55-year-old German, who has lived in the UK since 2012, was expected to serve half of his sentence behind bars but was released on Thursday morning and is due on a flight to be deported from the UK, the PA news agency understands.
He is thought to have been transferred to a lower security jail for foreign criminals awaiting deportation in May - Category C Huntercombe Prison near Henley-on-Thames in Oxfordshire - after previously reportedly being held at Category B Wandsworth Prison in south-west London.
The six-time grand slam champion qualified for automatic deportation because he is a foreign national who does not have British citizenship and received a custodial sentence of more than 12 months.
Becker's former spokesman explained the plan last month as he released this statement:
"We are pleased for Boris that he may qualify for an early release and be able to travel to Germany, albeit England has been his home for many, many years. I'm sure it will mean a lot to him and his family to be reunited for Christmas."
Becker's ex-wife has said telling their 12-year-old son that his father was going to prison was "the hardest thing I ever had to do".
Speaking on Piers Morgan's Uncensored show earlier this year, Sharlely "Lilly" Becker defended her former husband following his "harsh" two-and-a-half year jail term after being convicted of bankruptcy fraud.
When asked how she reacted at the sentencing, Ms Becker told TalkTV: "I completely broke down.
"I couldn't believe what I was hearing because I was convinced, until the judge made her verdict, that he was going to get a little bit lighter than two and a half years.
"I had to keep it together and I don't know how I did it."
Ms Becker added: "We all pulled together - the ex-wife, the kids, his current girlfriend Lilian - the first thing we did was reach out to each other.
"It's hard because it's public, it's everywhere.
"It's hard because everyone has an opinion about it, rightly so.
"I'm here to show everybody that he has a bunch of really strong women behind him, and who are here not to speak for him, but to protect him."