Abdulemam, known as the "Bahraini Blogger", had been sentenced to 15 years in prison on charges that he was part of a terrorist organisation.
He spent two years in hiding after a royal pardon was revoked.
Abdulemam escaped in a secret compartment of a car up a causeway that joins Bahrain to Saudi Arabia.
According to Atlantic Magazine, from there he was smuggled along the Gulf in a fisherman's boat to Kuwait.
He crossed into Iraq and took a regularly scheduled flight to London, where the magazine says he was granted asylum.
A source close to Abdulemam's family confirmed to the BBC that he had arrived in London.
Critical blogs
Abdulemam's troubles began when he started to write articles critical of the ruling Al Khalifa family.
The Al Khalifas are Sunni Muslim in a country with a Shia Muslim majority. Shia have long complained of discrimination.
Abdulemam worked as an IT specialist for the Bahraini airline Gulf Air. In his spare time he blogged.
But he was sacked from the airline after he was arrested in September 2010 and accused of being part of a terrorist organisation.
He was charged with spreading false information and linked to Bahraini opposition figures who had been arrested in August of that year.
Like Mr Abdulemam, all of the arrested men were Shia. Academics, a dentist, a geologist, and several clerics were among those held.
They all protested their innocence and were in fact pardoned by King Hamad and released in February 2011.
But following the crushing of the pro-democracy movement in March 2011, orders went out to re-arrest the men.
Ali Abdulemam went into hiding in Bahrain and managed to escape capture.
In an interview with the BBC in December 2010, his wife Jenan al-Oraibi told the BBC:
"Ali does not belong to any political party. He just writes his opinion. He has a free pen. That is exactly his crime. He has a free pen".
Mr Abdulemam's flight from the kingdom will cause the government there some embarrassment.
Along with other GCC (Gulf Cooperation Council) countries, Bahrain has cracked down hard on internet activism.
Now one of its critics, a hero among online activists, has slipped out of their grasp.
Ali Abdulemam, a prominent blogger in Bahrain, has been smuggled out of the troubled Gulf kingdom and taken refuge in the UK, the BBC has learned.