Contact with Syria
"The three Israelis were charged with spying and having contact with the enemy," Mickey Rosenfeld, a police spokesman, said.
The defendants were also charged with planning to kidnap a man believed to be a Syrian pilot who defected to Israel in 1989.
"They planned on kidnapping him and sending him back to Syria," the spokesman said.
The lawyers of the three suspects called the indictment against their clients "exaggerated" and said that they denied the charges brought against them.
The defence team complained that they were not able to address the claims made in the indictment as they have not had access to material from the police investigation.
Masarweh is a well-known political activist from Baka al-Gharbiyeh, who has been active over recent years on behalf of political prisoners jailed in Israel.
He has been arrested in the past and has spent some time in prison.
Fida al-Shaar was arrested at Ben Gurion Airport on July 10 when he was on a return flight from Paris.
His father, Majid, was arrested a few weeks later in Majdel Shams, the main town on the Golan Heights which Israel captured from Syria in the 1967 Six-Day War.
Israel unilaterally annexed the Golan in 1981, a move not recognised by the international community.
The vast majority of the 18,000 mostly Druze Syrians - all that's left from the Golan's original population of 150,000 - have refused to take Israeli citizenship.