Those arrested at Jakarta's Soekarno Hatta airport at dawn included a couple and their 10-year-old child, with police saying they were attempting to travel on fake passports.
The alleged organiser of the trip was also captured after the arrests.
"They admitted during an investigation that they want to carry out jihad and be martyrs in defending (IS)," said Jakarta police spokesman Rikwanto.
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"We hope to find out more details from the organiser, including who funded the trip," he added.
The number of IS supporters embarking from Indonesia soared to 264 in October from 86 in June, the National Counter-Terrorism Agency (BNPT) chief Saud Usman Nasution was quoted as saying in the Jakarta Post.
In total, an estimated 514 Indonesians have gone to Syria and Iraq to fight alongside IS -- around half of them students or migrant workers based in nearby countries, according to Nasution.
A large number of Muslims around the world have gravitated towards the radical group, which this year declared a caliphate spanning territories it captured in Syria and Iraq.
Indonesia has waged a crackdown on terror groups over the past decade following attacks against Western targets, including the 2002 Bali bombings -- a campaign that has been credited with weakening key networks.