The live stream was sold for a fee. The two men made about 7 million won (Rs 4,25,000) from their caper.
South Korean police have arrested two men for using illegal spy cameras at motels to film and livestream videos of about 1,600 guests, raking in roughly 7 million won ($6,200) over the past three months, police said on Wednesday.
Illicit filming has surged with growing use of mobile devices and South Korea's pop music industry is reeling from a scandal over singer and television celebrity Jung Joon-young, accused of having shared videos he took secretly during sex.
Police said the men, and two others, posed as customers to secretly install the cameras, obtained online from overseas, in 42 rooms at 30 places around the country since last August.
The footage from the cameras, hidden in television boxes, sockets and hair dryer holders, was broadcast live on a website, police added.
"It was the first case we caught where videos were broadcast live online," they said in a statement.
More than 6,600 cases of illicit filming were reported to police last year, or about a fifth of all sexual abuse cases investigated, up from 3.6 percent in 2008, prosecutors have said.
Last year, tens of thousands of women took to the streets of Seoul, the capital, to protest against the practice and other sexual violence, and demanded stricter punishment.
The law was amended last November to toughen penalties not only for illegal filming but also distributing images without consent, which could bring jail terms of up to five years or fines of up to 30 million won.
The K-pop scandal also involved Lee Seung-hyun, a member of boy band BIGBANG who is better known by his stage name, Seungri. The 28-year-old is suspected of paying for prostitutes for foreign businessmen to drum up investment in his business.
Seungri has denied wrongdoing.
On Thursday, a Seoul court reviewed an arrest warrant for Jung. In a statement, he admitted all the charges against him.