The Chiba District Court said it found Perth woman Donna Nelson guilty of violating the stimulants control and customs laws.
It ordered her to pay a fine of one million yen ($A10,000) in addition to serving a prison term.
Nelson was arrested at Japan's Narita International Airport just outside Tokyo on January 3, 2023, when customs officials found about two kilograms of phenylaminopropane, a stimulant, hidden under a false bottom in a suitcase she was carrying as checked luggage.
Nelson, 58, told the court she did not know that drugs were hidden in the suitcase and she was carrying them for a man she thought she loved and hoped to marry.
The Chiba court found Donna Nelson guilty of violating the stimulants control and customs laws. (AP PHOTO)
The man, whom she met online in 2020, told her he was the Nigerian owner of a fashion business.
In 2023, he paid to travel to Japan via Laos, and asked her to collect dress samples from an acquaintance in Laos, her lawyers said.
She was supposed to meet the man in Japan but he never showed up, according to prosecutors.
Nelson has already been in custody for nearly two years.
The court said 430 days of that will be counted toward her sentence.
Presiding Judge Masakazu Kamakura said that although Nelson was deceived, she had a sense that something was wrong with the arrangement and that something illegal could be hidden in the suitcase, and she could have stopped.
However, the judge said there was room for sympathy and imposed a shorter sentence than would be typical for the amount of drugs she was carrying.
Members of Donna Nelson's family attended the trial and saw her for the first time since her arrest. (AP PHOTO)
Prosecutors demanded 10 years in prison and a fine of three million yen in their closing argument in November.
Nelson's lawyer Rie Nishida said the ruling was unjust and did not make sense, and that she planned to appeal.
On Wednesday, Nelson dropped her head and was seen sobbing as she listened to the verdict in the witness seat in front of a panel of judges.
One of her daughters, Kristal Hilaire, was also seen wiping away tears as she looked on from her seat in the audience.
Several other family members who attended earlier sessions, seeing Nelson for the first time since her arrest nearly two years ago, returned home before the verdict.
