SEOUL—On a humid summer afternoon here, air-raid sirens suddenly blasted through downtown Seoul—the first sign most residents would have of a North Korean attack.
In Gwanghwamun square, tourists wearing rented traditional hanbok costumes kept snapping selfies. Passersby continued to hustle on their way as a brigade of a few dozen middle-aged men and women in yellow jackets struggled to herd people into nearby subway stations.
South Korea holds regular civil-defense drills, but on the streets of the capital Wednesday, the sirens were greeted largely with complacency, despite heightened concern about the threat posed by North Korea.
It was the country’s 404th civil-defense drill, a 20-minute nationwide exercise conducted roughly twice a year—less frequent than they once were—as a rehearsal for a North Korean attack.
The drills, which began in 1975 and are sometimes part of joint U.S.-South Korea military exercises, have become routine for civilians in a country that remains technically at war with its northern neighbor after an armistice agreement in 1953.
Cars are instructed to stop when the siren sounds. But when The Wall Street Journal witnessed the exercise at 2 p.m. on Wednesday, none of the vehicles appeared to do so. After about 10 minutes, though, some drivers eventually came to a halt.
In one subway station entrance, Lee Chang-yong, a 33-year-old consultant, stood glancing at his watch as he sipped an iced coffee. Mr. Lee hadn’t gone fully underground, as the rules dictate, and stared instead in the direction of his destination.
“I’m going to be late for my meeting,” said Mr. Lee, who complained that he had been caught in the drill while waiting for a bus. “I wouldn’t have done anything if I was still in my office.”
Alongside him, Lee Seong-su, a tour guide who has no relation to the first Mr. Lee, tried to keep a group from Taiwan entertained as they waited for the drill to end.
“I didn’t know there was a drill today. I just came here because I was told to do so by those people in the yellow jackets,” he said, pointing to some district government officials who were trying to corral people milling around in the square.
One of his clients, Chang Chih Pen, who runs a tour bus company in Taiwan, said it was hard to see anyone taking the drills seriously. “We have similar drills in Taiwan, but it’s more strict,” he said. “There are more people managing it and it lasts longer.”
South Korea’s Ministry of the Interior and Safety, which oversees the drills, has tried in vain to boost public enthusiasm. While the ministry estimates that at least one-fifth of the country takes part in the drills, it says that is largely because schools and other public facilities have no choice but to join in. And even in those locations, there are questions about the effectiveness of the approach.
“It doesn’t really work,” said one high-school teacher in Gwangju, a satellite city southeast of Seoul, adding that most schools don’t have any underground shelters.
In an effort to garner more participation this year, the minister in charge participated in a live broadcast of the drill, while the government took out advertisements on popular websites.
There are 3,250 shelters in Seoul for its 10 million residents, according to the city government. In the event of an attack, each would need to house more than 3,000 people. Switzerland, which officials here say they consider to have the best practice in such matters, had more than 300,000 bunkers for its 7.6 million people in 2011—or about 25 people per shelter.
At a Starbucks outlet, 34-year-old Hwang Ji-young said she didn’t hear the sirens from inside the cafe. She was immersed in her book.
Ms. Hwang only found out about the drill from a news article that appeared on her smartphone afterward. A cashier at the coffee shop was puzzled when asked about the drill.
“I didn’t even hear the siren,” he said.
Write to Eun-Young Jeong at [email protected]