Sri Lankan police said Naomi Michelle Coleman, 37, was arrested at Bandaranaike International Airport in the capital, Colombo, after she arrived from India.
A police spokesman said she was arrested for "hurting others' religious feelings" after the tattoo of a Buddha seated on a lotus flower was spotted on her right arm.
Buddhism is the religion of the country's majority ethnic Sinhalese and Buddhist tattoos are seen as culturally insensitive.
After her arrest Coleman appeared before a magistrate who ordered her deportation.
The spokesman said she is currently being held at an immigration detention centre until deportation and said she would be removed "very soon - it could be tomorrow or the day after tomorrow".
Antony Ratcliffe was reportedly deported for showing a Buddha tattoo on his arm in March last year.
In 2011, Thailand's Culture Ministry said foreign tourists in Sri Lanka should be barred from getting tattoos of Buddha during their holidays because the practice was culturally insensitive.
And R&B star Akon was refused a Sri Lankan visa in 2010 and had to apologise to Sri Lankan Buddhists after his video for Sexy Chick, which featured a pool party in front of a Buddha statue, caused offence and protests in the nation.
A spokeswoman for the Foreign and Commonwealth Office confirmed they were dealing with the case of a detained British national.
She said: "We are aware of the detention of a British national in Sri Lanka on April 21. We are providing consular assistance."