In Bravely Default II, you’ll need lots of JP to level up the numerous jobs you can obtain. (Click here for a listing of all the jobs!) We’ve found that the below method is the easiest way to farm/grind JP.
Step 1: Max Out Freelancer Job
You’ll first need to max out the Freelancer job for all four party members, which is the default starting job in the Prologue. Once this job reaches level 12, you’ll have learned both the JP Up and JP Up and Up abilities. Equipping these two skills will increase the amount of JP you earn by x 1.7.
Step 2: Travel to the Underground Reservoir in Savalon
In Chapter 1, the party will make their way to Savalon as part of the story. During your search for the Water Crystal, you’ll gain access to the Underground Reservoir. Once you clear the dungeon, use the teleport pad to move to the center of the dungeon. Head north making your way through a mine area ending up on a secluded beach. Here you will find the rare monster Mushussu.
Step 3: Defeat Mushussu
Mushussu is the enemy your going to grind on for JP. Upon defeat, the beast awards 314 JP and 2178 EXP. If you add in the 1.7 JP bonus from the two Freelancer skills mentioned above in step 1, this means you’ll be getting about 533 JP per fight. By entering the reservoir and then heading back to the beach, the monster respawns for you to fight again. At level 30, I didn’t have any trouble taking him down in about 5 minutes per run. My setup was making the job I wanted to level the main job while setting the Freelancer to my sub job. I then used Brave once so I could use two Body Slams from the Freelancer class targeting the 2 adds first. When your first starting out, it might be better for you to have one party member set with the sub job of a White Mage so that you can heal as needed. If doing this, make sure you also have the Solar-Powered ability from the White Mage job and the Lunar-Powered ability from the Black Mage job. This will allow you to build up MP as the fight goes on. I’d also recommend buying and equipping 4 Star Pendants, which prevent your party from being poisoned, as the boss can inflict this status aliment. If your making good time it should take 30 -45 minutes to max out one job per party member.
Step 4: Additional Tips
As you progress further in the game, you’ll unlock more abilities to make this process go faster. The biggest one is the Sub-Job BP Saver ability you get from leveling up the Pictomancer class which is obtained from defeating the Chapter 2 boss. This ability reduces the cost of skills that use up BP by one. This means that with the Freelancer job set as the sub job, you can use four body slams per character dealing massive damage making the boss go down much quicker. At level 60 with four body slams per character, it takes less than 60 seconds to defeat the Mushussu and its 2 adds. I was able to level up a job from level 1 to 12 in about 15 minutes.