The unidentified woman was arrested at the country's main international airport on Monday and appeared before a magistrate who ordered her deportation, police said in a statement.
The statement said she had an image of the Buddha seated on a lotus flower tattooed on her right arm.
"She was taken before the Negombo magistrate who ordered her to be detained prior to deportation," it said, adding that she was arrested shortly after her arrival on a flight from neighbouring India.
It did not say what charges were brought against her, but Sri Lanka barred another British tourist from entering the island in March last year for showing "disrespect" to Buddhism by having a Buddha tattooed on his arm.
Sri Lanka, a majority Buddhist nation, is highly sensitive to perceived threats to the religion.
In August 2012, three French tourists were sentenced to six months in jail, which was suspended for five years, for kissing a Buddha statue in what the authorities considered was a sign of disres