A dog walker discovered the large marine mammal on the beach along eEplanade Avenue around 6 a.m. Sunday.
"Just so massive in size," said Pacifica resident Nicole Strasser. "And usually people go in boats just to see these creatures in their natural environment frolicking and playing, they're just like elephants."
This is the third, dead whale to wash ashore in Pacifica since mid-April.
Scientists haven't determined what killed those other whales, along with another that washed up in Half Moon Bay.
PHOTOS: Dead sperm whale washes ashore in Pacifica
PHOTOS: Decomposing whale washes ashore in Half Moon Bay