The three, from the state-run Korea Broadcasting Corp., were detained when their baggage failed an explosives inspection, the Korea Times said.
"The U.S. soldiers knew we were journalists," one of the three journalists, Jeong Chang-jun, told Yonhap News. The two others were identified as Shin Kee-ho and Kang Seung-hyuk.
"We showed them our ID cards and said we were South Korean journalists," Jeong said.
Many South Korean journalists are expected to go to Iraq because of South Korea's plans to send 3,000 soldiers there next month to support the rebuilding of the country.
About 600 South Korean medics and engineers have been in Iraq since last spring.