For the majority of the Friday the 13th franchise, Jason had almost no weaknesses. However, later films chose to give him a crippling fear of water. This was due to the circumstances of his death when he drowned in Crystal Lake as a child.

Some fans also theorize if Jason could defeat Thor -- the God of Thunder from Marvel Comics. However, it's likely Thor decimates Jason. There is almost no point even questioning this, given Thor is a literal god. Thor's strength dwarfs Jason's.