The three are suspected of “obtaining and storing large amounts of chemicals and other equipment with the aim of killing and wounding other people,” the prosecution authority said in a statement.
“If the terrorist crime had been carried out, it could have seriously hurt Sweden.”
The trio were also charged, along with three other people, with financing terrorism. Prosecutors accuse them of sending money abroad to fund the so-called Islamic State's operations.
All six have denied the charges against them. The trial is expected to open on January 7th.
The men, aged between 30 and 46, originally hail from Uzbekistan and Kyrgyzstan. Their residency status in Sweden could not immediately be verified.
Five of the six have been in custody since a police raid in Strömsund, 600 kilometres (375 miles) north of Stockholm, in late April. The sixth man is not in custody.
During the April raid, neighbours told the Dagens Nyheter newspaper they saw police removing about 15 large plastic containers from a shed on an empty property.
According to Dagens Nyheter, at least one of the suspects had been in contact with Rakhmat Akilov, a radicalized Uzbek asylum seeker who mowed down pedestrians in Stockholm with a stolen truck in April 2017, killing five people. Akilov was sentenced to life in prison in June 2018.