The trial was to have started on Nov. 6, but authorities said they delayed it because one of the Americans, who was freed on bail, had not been summoned to return to the country to appear in court.
Their lawyer, Masoud Shafiei, said he received an official notification Sunday of the new trial date.
Sarah Shourd was freed in September and returned to the United States. Her fiance, Shane Bauer, a native of Onamia, Minn., and their friend Josh Fattal remain in prison.
Shourd has denied the charges. She says they were hiking in northern Iraq and inadvertently crossed an unmarked border into Iran when they were arrested in July 2009.