Contradiction with Genesis 14:1
This verse lists kings involved in an alliance against other kings, but they are not the same kings or context as those mentioned in Joshua 12:12.
Genesis 14:1: And it came to pass in the days of Amraphel king of Shinar, Arioch king of Ellasar, Chedorlaomer king of Elam, and Tidal king of nations;
Contradiction with 1 Samuel 15:32
Agag is described as a king here, contradicting the kings listed in Joshua 12:12 because he is not one of the kings defeated by Joshua.
1 Samuel 15:32: Then said Samuel, Bring ye hither to me Agag the king of the Amalekites. And Agag came unto him delicately. And Agag said, Surely the bitterness of death is past.
Contradiction with 1 Kings 11:1
This verse refers to various kings allied with Solomon, which contradicts Joshua 12:12's focus on Canaanite kings defeated by the Israelites.
1 Kings 11:1: But king Solomon loved many strange women, together with the daughter of Pharaoh, women of the Moabites, Ammonites, Edomites, Zidonians, [and] Hittites; [together...: or, beside]
Contradiction with 2 Kings 25:7
This verse describes the execution of the Babylonian king Zedekiah's sons and his blinding, contradicting Joshua 12:12 because it's unrelated to the Canaanite kings mentioned there.
2 Kings 25:7: And they slew the sons of Zedekiah before his eyes, and put out the eyes of Zedekiah, and bound him with fetters of brass, and carried him to Babylon. [put...: Heb. made blind]
Contradiction with Esther 1:1
King Ahasuerus ruled over a vast empire far larger than the geographical context of the kings in Joshua 12:12.
Esther 1:1: Now it came to pass in the days of Ahasuerus, (this [is] Ahasuerus which reigned, from India even unto Ethiopia, [over] an hundred and seven and twenty provinces:)
Contradiction with Jeremiah 46:2
This verse speaks of Pharaohnecho king of Egypt, who opposed the Israelites, contrasting with the kings defeated in Joshua 12:12 where Egyptian rulers are not mentioned.
Jeremiah 46:2: Against Egypt, against the army of Pharaohnecho king of Egypt, which was by the river Euphrates in Carchemish, which Nebuchadrezzar king of Babylon smote in the fourth year of Jehoiakim the son of Josiah king of Judah.