The Foreign Office in London confirmed the release, saying the “priority now is to get her to a place of safety.”
Tebbutt, 57, was taken on September 11 last year from a remote beach resort near the Kenyan-Somali border by armed men who shot dead her husband David.
“The British lady who was kidnapped from Kenya was just released,” said Mahmoud Hirsi, an elder in the Addado region.
“She is a free woman, but I cannot discuss the technical details of her release,” he added.
“The plane had the hostage and three other people on board,” he said.
She was released in the Addado region, about 50 kilometers (30 miles) from the Ethiopian border and about 500 kilometers (300 miles) northeast of Somalia’s capital Mogadishu.
Two witnesses said they saw Tebbutt boarding an airplane that took off from Adado airport. BBC footage showed Tebbutt wearing a green headscarf running towards a plane in a flat, barren landscape. A man in a bush hat and safari jacket was seen accompanying her, his arm around her shoulders.
A pirate who identified himself as Ahmed told Reuters Tebbutt, who is in her 50s and had a hearing defect, had been handed over to regional administration officials early on Wednesday after receiving a ransom that had been air dropped.
“I am very relieved to have been released,” Tebbutt was quoted as telling Britain's ITV News. “... I am just happy to be released and I'm looking forward to seeing my son who successfully secured my release. I don't know how he did it, but he did. Which is great.”
It was not clear who paid the ransom or how much was paid.
Tebbutt, is believed to have been held by gunmen in a lawless region notorious for its pirate gangs who had held Paul and Rachel Chandler, the British couple seized from their yacht in 2009 and held for a year.
“The people in Addado and the surrounding areas pushed the local leaders to do something about the hostage. I heard that since the abduction, she was held by three different groups,” said Abdullahi Yasin, a driver in Addado.
Security was beefed up in the region after U.S. special forces swooped in by helicopter on a night raid in January to rescue an American woman and a Danish man working for a demining aid agency in the area.
Pirates in the region also hold hundreds of hostages seized from ships in the Indian Ocean, and have in the past demanded multi-million dollar ransoms for the release of captives and of boats.
The Tebbutt’s, from the town of Bishop’s Stortford in southeastern England, were attacked in their room at night. They were the only guests at the upmarket Kiwayu Safari Village, some 40 kilometers (25 miles) from the Somali border.
A French woman, Marie Dedieu, kidnapped from the same coastal area three weeks later, died in captivity.
In October, gunmen captured two Spanish aid workers from Kenya’s Dadaab refugee camp, who are believed to be still held in Somalia.
The spate of attacks prompted Kenya to send in troops and tanks into southern Somalia in October to attack the al-Qaeda allied Shebab insurgents, who Nairobi blamed for the attacks.
The extremist insurgents, who control large parts of southern and central Somalia, have always denied involvement in the kidnappings, but do admit to abducting Kenyan officials they call prisoners of war.