Reach the indicated job level to unlock the next job in that class.

Job	How to unlock
Archer	Reach level 2 Squire.
Arithmetician	Reach level 5 White Mage, level 5 Black Mage, level 4 Mystic and level 4 Time Mage.
Bard	Reach level 5 Summoner and level 5 Orator; only as a male character.
Black Mage	Reach level 2 Chemist.
Dancer	Reach level 5 Dragoon and level 5 Geomancer; only as a female character.
Dark Knight	Completely Master Knight and Black Mage, crystallize 20 units, and reach level 8 with Dragoon, Ninja, Goemancer and Samurai.
Dragoon	Reach level 4 Thief.
Geomancer	Reach level 4 Monk.
Knight	Reach level 2 Squire.
Monk	Reach level 3 Knight.
Mystic	Reach level 3 White Mage.
Ninja	Reach level 5 Thief, level 4 Archer, and level 2 Geomancer.
Onion Knight	Reach level 6 Squire and level 6 Chemist.
Orator	Reach level 3 Mystic.
Samurai	Reach level 5 Monk, level 4 Knight, and level 2 Dragoon.
Summoner	Reach level 3 Time Mage.
Thief	Reach level 3 Archer.
Time Mage	Reach level 3 Black Mage.
White Mage	Reach level 2 Chemist.