KUTA, Indonesia — The resort island of Bali fell quiet over the weekend as the authorities shut down its airport and seaports, and switched off all radio and television transmissions. Its streets, normally jammed with tourists, were deserted as security guards patrolled the island, ensuring that locals and foreigners alike stayed indoors, and even exhorting them to turn off their lights.

Balinese security guards, called pecalang, helped enforce silence in Kuta

The authorities closed down Bali not to stamp down on political unrest, but to mark the annual Day of Silence, a Balinese Hindu holiday called Nyepi that ushers in the New Year. For a full 24 hours starting at 6 a.m. Saturday, Balinese Hindus were urged to remain silent and engage in introspection. Bali, which first became known as a destination among hippies from the West a couple of generations ago, tuned in and dropped out, at least for the day.

“Have a quiet time! Enjoy the silent day!” Wayan Sutama, 51, a traditional security guard called a pecalang, called out to a group of potentially unquiet Australians gathered on a terrace overlooking the beach here. With a half-wary smile, he flashed them a thumbs-up.

In Kuta, a rowdy beach resort on the southern tip of the island, only roosters and pigeons, usually drowned out by the din, could be heard Saturday. The pecalang peered down side streets in search of transgressors but found only other pecalang looking back, or the occasional stray cat.

As the last redoubt of Hinduism in Indonesia, the nation with the world’s largest Muslim population, the island of Bali has been attracting increasing numbers of outsiders in recent years, thanks to its booming tourism industry. While Hollywood romanticized Bali in the recent movie “Eat Pray Love,” Indonesians, mostly Muslims from the islands of Java and Sumatra, have been gravitating here looking for jobs. The tension between local tradition and outside forces is perhaps at its most intense in Kuta, where Islamic extremists bombed a nightclub in 2002, killing 202 people, and bombed three restaurants in 2005, killing more than 20 people.

In reaction, officials in Bali have been reinforcing local customs, especially those of Nyepi. Three years ago, they began sealing off Bali from the rest of Indonesia for 24 hours after tour organizers were caught smuggling in tourists on the Day of Silence as part of “Nyepi packages.” At the same time, the authorities banned radio and television and, last year, extended the ban to all satellite transmissions.

“The lesson from the Bali bombings was to return to our traditions and not be too influenced by outsiders,” Mr. Sutama said Saturday. He and another pecalang, Nengah Renda, 51, spoke as they faced a memorial for the bombing victims on Kuta’s main commercial strip; behind them, a lingerie shop called 69Slam featured an image of a woman with a man on all fours attached to a dog leash.

The day before, in one of the many local temples squeezed between shops in Kuta, the residents of a neighborhood called Pande Mas had been putting the final touches on their ogoh-ogohs, effigies 20 feet tall representing evil spirits that would be burned later. “After chasing away the evil spirits, we have Nyepi to purify our minds, to reflect on what we did in the past year and to engage in introspection,” said Made Mastra, 52, the neighborhood chief. “Then we will be clean to enter the new year.”

Neighborhood boys, who can often be seen rubbing shoulders on Kuta’s streets with Australian, Asian and European tourists, were required to make their own ogoh-ogohs. On Saturday, a group of boys, led by Wayan Putra Setiaman, 14, said they would obediently stay home, not daring to step outside lest they be caught by the pecalang.

They would not be allowed to use their television sets.

“But we can send SMSs to our friends as long as we’re quiet?” he said, zeroing in on a subject under debate among the pecalang.

How about video games?

“Yes,” he said.

“No!” said another boy, Wayan Wima Putra, 10, said, tapping the older boy across the chest.

“No,” the older boy corrected himself, explaining that videogames connected to television sets were forbidden but that portable ones were O.K.

Even as Bali has reinforced its traditions, some outsiders said it had lost a bit of its legendary openness. Ucok, 41, the manager of a tattoo shop who moved to Bali from Sumatra 15 years ago, said he and other Muslims felt a little “discrimination.”

“Since the bombing, the locals are more suspicious toward Muslims,” Ucok said, adding that outsiders would nonetheless keep coming here. “Bali is like sugar. Ants come to it.”

Made Darsana, 59, the deputy chief of one of Kuta’s three subdistricts, said outsiders were occupying an increasingly larger share of the population.

On Saturday, Mr. Darsana and a dozen pecalang were taking a break from their patrol at a temple where they quietly shared fried rice. Mr. Darsana, who spoke English with an unmistakably American accent, said he learned English about 40 years ago from an American Indian named Joe. Joe was among the hippies who discovered Bali, back when Kuta had perhaps a single guesthouse, Mr. Darsana said. “Life isn’t about material things, about tall buildings,” he said. “It’s about being one with the world. That’s the core teaching of Hinduism. I didn’t know this when I was younger. You learn these things as you live. Been there, done that.”

With development and the influx of outsiders, Bali’s environment has been irreparably damaged, he said. Outsiders now owned almost all the major businesses in Kuta.

“It’s sad,” Mr. Darsana said. “We now have only our culture.”

His smile and constant cheerfulness, though, belied his expression of loss. Despite the Day of Silence, Mr. Darsana grew increasingly loquacious as he reminisced about his hippie youth — hanging out with Joe, mastering the surfboard as well as the bong, taking a three-day drive all the way to Jakarta. “And my girlfriend was in the back,” he added, to roars of approval from the subdistrict chief as the other pecalang nearby immediately chided him in unison, “Shhhh!”

Sheepishly, Mr. Darsana mentioned that, at night, he himself would make sure that his neighbors turned off any electric lights or candles. “It’s going to be like Kuta in the 1960s,” he said. After a long pause and perhaps some memories left unmentioned, he added. “Been there, done that.”