Julian Ponder, 43, from Brighton, was convicted for his role as an accomplice to Sandiford, 56, from Redcar, Teesside, who was sentenced to death for smuggling £1.59 million of cocaine into Bali.
Ponder was found guilty of possessing drugs and also fined one billion rupiah (£65,000), by a court in Bali.
Sandiford intends to appeal. She was accused by the Bali court of damaging the image of the resort island and received the sentence despite prosecutors only asking for a 15-year jail term.
Another British woman, Rachel Dougall, was arrested with Ponder and Sandiford by Indonesian police last May.
At the time, Dougall, who has a young daughter, insisted she was the victim of a "fit-up" and Ponder claimed he was "trapped".
Ponder's lawyer claimed he was told Sandiford would deliver a present for his child's birthday, but when he met her, he was arrested. Sandiford claimed she got involved because her children's lives were in danger.
Kent University academic Jennifer Fleetwood, an expert on coercion in the international drug trade, said she thought Sandiford had been coerced into acting as a drugs courier.
Charity Reprieve said "vulnerable" Sandiford was targeted by drug traffickers.
Law firm Leigh Day said Sandiford has not had proper legal representation since her arrest.