As revealed by planetfootball.com earlier in the month, Bert van Marwijk`s side tabled a bid with Pusan Icons for the capture of the talented right winger.
PSV Eindhoven, Tottenham and Southampton were also keen, but Feyenoord were the most active and agreed a deal over the weekend.
Song travelled over to Holland on Sunday, and the club have confirmed to planetfootball.com that terms have been agreed.
Senior manager Fred Blankemeijer said: "He is having a medical examination with our staff today.
"We do not envisage any problems, but his contract has not yet been signed.
"We have agreed a deal and expect him to sign soon, we just need the consent of the associations.
"He will go back to Korea tomorrow, but will return as soon as we get approval from our association.
"He will not be ready to play at the weekend, but hopefully inside two weeks."
The capture of the 23-year-old could pave the way for Australian ace Brett Emerton to leave De Kuip, as he has been linked with Leeds and Liverpool over the summer.
