Judith Tebbutt said in a statement she was hugely relieved to be free and overjoyed to be reunited with her son, Ollie. She said he had played a key role in securing her release.
"This, however, is a time when my joy at being safe again is overwhelmed by my immense grief, shared by Ollie and the wider family, following David's passing in September last year," she said. "My family and I now need to grieve properly.
"I hope that while I adjust to my freedom and the devastating loss of my husband, that I and my family will be allowed space, time and most of all privacy, to come to terms with the events of the last six months," her statement said.
Tebbutt was flown out of Adado, Somalia, to the Kenyan capital, Nairobi.
"The priority now is to get her to a place of safety," said a spokesman from the British Foreign and Commonwealth Office.
Tebbutt's release came after lengthy negotiations between elders in Adado and local authorities, said Omar Mohammed Diirey, a regional administration official in central Somalia.
He described Tebbutt as "very tired and pale but fine otherwise."
Somali Information Minister H.E. Abdulkadir Hussein expressed relief at Tebbutt's release.
"The Somali government will assist in any way it can in the capture and the arrest of the kidnappers who murdered her husband and kept her hostage since September 2011," he said, urging assistance from the international community in thwarting the extremism and piracy plaguing the Horn of Africa nation.
Tebbutt was abducted from a safari lodge in the popular Kenyan tourist town of Lamu in September. Gunmen fatally shot her husband, David Tebbutt, when he resisted, according to Kenyan police.
Judith Tebbutt was spirited away aboard a pirates' speedboat.
