In a short alert, the IMB's Kuala Lumpur-based piracy reporting centre said the vessel was "released" earlier today and "is now proceeding to a safe port".
The centre said the tanker was taken by pirates but did not say whether there were any losses, and could not be reached for further details.
The owners lost contact with their vessel early Thursday while it was in the Gulf of Guinea off the coast of Togo, leading the IMB to issue a warning to other ships in the area.
Pirates in the area typically target fuel cargo, loading it onto other ships to sell on the lucrative black market, rather than seek ransom to release ships, the IMB said.