Leaders of the country's Christian minority said they were determined to hold services as normal, but acknowledged that fears of bombings had dampened the festive spirit.
"We are going to celebrate Christmas with prayers at our church but we have to be alert to the fears of bombings," said the Rev. Elsantide Sangkide. "We hope God will prevent us from suffering this Christmas," he said.
Four years ago, bombs exploded at 11 churches across Indonesia on Christmas Eve, killing 19 people and wounding about 100. The attacks have since been blamed on the al Qaeda-linked terror group Jemaah Islamiyah.
The group, which allegedly has cells across Southeast Asia, was also blamed for the 2002 Bali bombings, which killed 202, a 2003 attack on the J.W. Marriott Hotel in Jakarta and a blast at the Australian Embassy in September.
Sangkide's church is on Sulawesi island in central Indonesia, which has seen a series of recent attacks by Islamic militants on Christian villages and places of worships.
In Makassar, the capital of South Sulawesi province, armed police will escort priests from their homes to churches on Christmas Eve, said local police chief Saleh Saaf.
Last week, several foreign governments warned that Islamic militants were planning more attacks on Western targets to coincide with the holiday season.
Australia's warning was unusually specific, saying it had information that the group was ready to attack one of the country's three Hilton hotels.
More than 140,000 police officers are safeguarding churches, malls and hotels, said national police spokesman Maj. Gen. Paiman. Intelligence operations have also been stepped up, officers say.
"Around the country about two-thirds of the total police force will be out and working around the clock," said Paiman, who goes by a single name.
Christians make up around 8 percent of the country's 210 million people, of which more than 80 percent are Muslim. Relations between the faiths are generally good in most of the country. But in central and eastern Indonesia, where Christian and Muslim populations are roughly equal, bloody fighting has erupted on several occasions since 1999.
By Irwan Firdaus