The defendants included five Moroccans, four Spaniards and a Brazilian, the National Court, which handles terror cases, said in a ruling.
They were "ready to wage an attack against institutions such as the police, banks or Jewish institutions in Spain at any time, or to join the ranks of Daesh," it added, using the Arabic acronym for IS.
The cell was based in Terrassa, not far from Barcelona, the Catalonian capital.
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Last year, another jihadist group killed 16 people in attacks there and on the nearby popular seaside city of Cambrils.
The 10, whose cell was called "Islamic Fraternity, Group for preaching jihad," were sentenced for "belonging to a terrorist organisation'" the court said.
The three leaders of the group were given 12 years in jail while the seven others got eight years.
In March 2015, the main leader of the cell, a Spaniard who had converted to Islam, proposed to kidnap and decapitate an "infidel" whom he had already identified, film the killing and then broadcast the video online before fleeing to Syria.
He had previously proposed that the group "commit an attack against the Catalan parliament, which no one had objected to," according to the court ruling.
"He also justified decapitations and talked about making handmade bombs to commit attacks."
Police found documents calling for jihad at his home and books on European organisations such as the Basque separatist group ETA or Germany's far-left Red Army Faction, the ruling said.
Members of the cell had also gone on a recce in Barcelona, the Catalonian capital, where they took photos of the train station, a luxury seaside hotel, a shopping mall and a police station.
One member went to Syria in April 2014 and died in Fallujah in Iraq the following year.
Three others tried to follow in his footsteps at the end of 2014 but were detained at the border between Bulgaria and Turkey.
According to the interior ministry, close to a third of all arrests for "jihadist terrorism" in Spain were made in Catalonia last year.