The Maritime and Port Authority of Singapore (MPA) reported the incident occurred on 1 December at about 3.00 pm local time.
PSA Singapore has now disclosed that all 15 containers were retrieved on 2 December night.
MPA deployed two patrol crafts to monitor and cordon off the affected area to facilitate recovery work by PSA Corporation Ltd.
MPA’s Port Operations Control Centre restricted all vessel movements in the vicinity of Keppel Terminal until recovery.
There had been no reported injuries and no immediate impact to port operations, according to a PSA spokesperson.