The animal was spotted by Leo van Toly who was travelling onboard a Dutch merchant ship.
In video captured by Mr Toly a flash of white is glimpsed gliding through the swell before the beast disappears below the waves.
Mr Toly said he’s still pinching himself over the sighting.
The sighting recalls Herman Melville’s famed 1851 book ‘Moby Dick’, in which obsessive captain Ahab seeks revenge on a giant white sperm whale that took his leg.
However, as Mr Toly only partially sighted his white whale it’s unclear whether it has albinism.
Another skin condition called leucism can also cause partial loss of pigmentation in animals.
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Sperm whales are mostly grey can, reach 18 metres in length, and are the largest toothed predator on earth.