This is a fun build to make your enemies table flip. Don't try this in ranked, Jayce jungle can be outplayed quite easily by early invades.

Something to keep in mind: Jayce is a really slow jungler, he need a lot of time to clear his jungle properly.

But he has a high kill potential when he gets some speed.
Whit his all ins (6 skills) he can easily burst enemy's down.

Knowing when to go in is the key to master him in the jungle.
You should not risk to die because of a risky kill, let your lainers do there job first.

Your first Goal: Stay at minute 3:15 in the river with 100% HP and 6 skills ready to claim your scuttle or first blood.

Route
You always start at your red buff and do a three camp clear to scuttle:
- red buff
- blue buff
- gromp
- river

Reasons:
- red helps to clear the camps
- blue for the high xp value and limitless mana
- gromp will give you level 3 and heals you for the river encounter / scuttle (you will go into the fight with all 6 skills, and full health)

First smite early against the blue buff (you will need the second smite for the grump).

Wait for your second smite until it has 14 second CD (yes, you read right! Just dance and relax, this is how Jayce jungle works, you will be just on time for scuttle).

Use your second smite against grump to regenerate your health.

Use your Potion: Don't be afraid using your potion, your life should be >90% when walking into the river. Better one charge to much then dying with two charges in your inventory.

Normally, you place a ward to see if the enemy jungler comes to contest and make the scuttle in several seconds.

If your Mid / Top lane pushed well, ping them to helping you gaining a kill.
But you will focus more on the scuttle gold, you will need it more then a risky kill.

Push the scuttle always to a side where your liner has more pressure, so it can not be stolen easily.

Don't forget to start in your hammer form and use E first to break the scuttle shield.

It depends highly on your opponents starting position, I recommend to read some jungle pathing and decision guides.

My personal references when starting Blue side, top down:
1. Focus on scuttle, you will need the gold
2. Go Top / Mid gank only when its worth a kill (take the kill when you can, you are gold hungry)
3. Go Top Q+E combo for some damage and back farming (ping it properly)
4. Go back to Wolfs
5. Try capture bot side scuttle
6. Try a "save" bot side gank (only when its worth the time >70% chance for a kill + enemy's have no flash any more)
7. Go to Krugs
8. Backport, buying some swords and boots

When walking into a lane, start in melee form and use your predator.

Based on your situation:
- Use Q to close the gap
- Use W to make some AOE damage (never wrong)
- Use E to knock the enemy to your team mate or away from him when he is on low life
Swap in range form
- Use E on your current position to gain the movement speed
- Make an AA for the penetration debuff
- Use Q for more damage in combination with your E


Tips:
- Move between each attack, stay near your opponent
- Sometimes its worth to stay a bit longer in hammer form for the armor and MR bonus
- Use Flash + E OR Eclipse Movement Bonus + E to knock enemy's away from there save tower range
- Use your E first when you have the opportunity to gank directly from behind. The knockback will work even when the enemy try to use flash

To be able to master the jungle with Jayce, you should start to master Jayce Top/Mid first and then mastering jungle second with a easy jungle champion like Nunu.

When you first time jungle and want to try it with Jayce, you will have a hard learning curve.

Learn the basics like: Kitting jungle camps properly, what monster to focus first, how to rotate skills nicely, holding long CD skills ready when planing a gank, having a jungle route and a plan in mind all the time, looking at your mini map, etc.

Have fun with this guide and hopefully you will learn that the jungle is not so bad as it seams.

Be blessed by the creator of the universe!