Locals have enjoyed the rare sighting over the last few days, with more reported sightings early this morning just off Kinghorn.
It is unclear if there is just one whale in the waterway, however sightings of the animal have now occurred three days in a row.
The first sighting of the whale was reported on December 2nd on Scottish Humpback ID/ Forth Cetacean Sightings. and Forth Marine Mammals Facebook page.
There have been several reported sightings of whales in the last few months.
Each year around this time the Forth is often used by humpback whales as a feeding ground as they prepare to head further north.
Earlier this year, a Sei whae, which is an incredibly rare type of whale was spotted in the Firth of Forth.