Verses with the word leviathan in the Old Testament (4 verses):

Job 41:1
Canst thou draw out leviathan with an hook? or his tongue with a cord which thou lettest down?

Psalms 74:14
Thou brakest the heads of leviathan in pieces, and gavest him to be meat to the people inhabiting the wilderness.

Psalms 104:26
There go the ships: there is that leviathan, whom thou hast made to play therein.

Isaiah 27:1
In that day the LORD with his sore and great and strong sword shall punish leviathan the piercing serpent, even leviathan that crooked serpent; and he shall slay the dragon that is in the sea.