Lamichhane, who is not in custody, was not present when the sentence was handed down at a court in the Nepalese capital Kathmandu on Wednesday.
The 23-year-old – Nepal’s most high-profile cricketer – was found guilty of the offence last month.
Lamichhane’s lawyer Saroj Ghimire told Reuters he intends to appeal against the verdict in a “higher court”.
“We are not convinced about the decision of the court,” said Ghimire. “The court has whimsically declared Sandeep to be a convict. Sandeep will go to the higher court for justice.”
Lamichhane – who has played in Australia’s Big Bash and the Indian Premier League – was suspended as Nepal captain in September 2022 due to the rape accusation.
After a warrant was issued for his arrest, he was taken into custody after flying home to Kathmandu from playing in the Caribbean Premier League (CPL).
At the time, he said on Facebook he was returning to co-operate with the investigation and denied any wrongdoing.
Following his release on bail, Lamichhane returned to the Nepal side amid protests in February 2023 for a Cricket World Cup League 2 tri-series against Scotland and Namibia.
Players from both opposition nations refused to shake his hand, but Lamichhane continued to play for Nepal throughout 2023.
