The 20-year-old is widely regarded as one of Asia's most promising youngsters and has attracted the interest of Premier League clubs in the past.
Now a regular for the national team, Lee should have few difficulties obtaining a work permit which had been the main reason for clubs not approaching him.
And Kim Seung-tae, general manager of Ti Sports which represent Lee, confirmed Bolton are keeping tabs on the winger.
"Yes, Bolton have sent a scout to watch him play for South Korea. However, nothing has been discussed at this stage," he told the local media.
Lee's club FC Seoul were not aware of the scout's visit but are prepared to talk if the move benefits both parties.
"There were rumours about Lee, but we have had no contact from Bolton," FC Seoul general manager Han Woong-soo said.
"We are willing to talk. Lee is a key player for us but he can leave if it will help with his development."
Manchester City have also been mentioned as another possible suitor.
Prem W/out Top 4 2009/10 Win Outright: Bolton 66/1