Eleanor Hawkins, 23, from Derbyshire, was one of 10 people who stripped before taking photographs at the peak of Mount Kinabalu on 30 May.
Four of them - including Ms Hawkins - got three-day prison sentences for "committing an obscene act in public".
She said in a statement outside her home in Draycott that she had been "foolish" and was "truly sorry".
Ms Hawkins arrived at Heathrow this morning after being deported by the Malaysian authorities.
She said: "I know my behaviour was foolish and I know how much offence we all caused to the local people of Sabah.
"For that, I am truly sorry."
Her prison sentence was back-dated to reflect time already served and she was also fined 5,000 Malaysian ringgit (Â£860/$1,330) on Friday.
Prosecutors said the 10 tourists climbed the peak on the island of Borneo to enjoy the sunrise and then challenged each other to take off their clothes and pose for photographs.
It caused widespread offence in the region, and Sabah state deputy chief minister Joseph Pairin Kitingan said their "disrespect to the sacred mountain" caused an earthquake.
The magnitude 5.9 earthquake, on June 5, killed 18 people and left hundreds more stranded.
The trio who were jailed alongside Ms Hawkins - Dutch national Dylan Snel, 23, and Canadian siblings Lindsey, 23, and Danielle Peterson, 22 - have all left Borneo.
A British woman jailed in Malaysia for stripping off on a sacred mountain has apologised for causing offence.