Sinnoh Underground
Sinnoh Underground is a daily quest that can be started in Eterna City House 2. There is a 
3,000 fee for entering the underground.
It is one of the lesser known daily activities, but it can give some good rewards if you can find the Treasure Room.
The Underground
Rewards
One of the unique aspects about this activity is that it rewards the player with a chance to freely sync a Fossil. Furthermore, you will be rewarded with PvE Coins and some of the Valuable Items shown below.
Treasure Cave
| Item | Quantity | |
|---|---|---|
 |
TM313 - Earth Power | 1 |
|
TM245 - Scorching Sands | 1 |
 |
TM249 - Meteor Beam | 1 |
|
TM149 - Stone Edge | 1 |
|
TM26 - Earthquake | 1 |
|
TM150 - Stealth Rock | 1 |
 |
UpGrade | 1 |
 |
Dubious Disc | 1 |
 |
Protector | 1 |
 |
Razor Fang | 1 |
 |
Razor Claw | 1 |
 |
Pearl | 1-4 |
 |
Nugget | 1-4 |
 |
Big Pearl | 1-2 |
 |
Big Nugget | 1-2 |
Arboreal Area
Hisuian Growlithe
Hisuian Voltorb
| Item | Quantity | |
|---|---|---|
 |
Peat Block | 1 |
 |
Black Augurite | 1 |
 |
TM179 - Trailblaze | 1 |
 |
TM304 - Aura Sphere | 1 |