The Underground Path is a completely straightforward path connecting Routes 5 and 6, crossing beneath the currently inaccessible Saffron City.
There are, however, quite a few hidden items on the ground in the Underground Path, and they can be very tricky to find since the Underground Path looks mostly the same.
One helpful trick is to pay careful attention to your Pikachu or Eevee’s tail. It will shake as you approach items and shake more vigorously when you’re closer to them. You can use this to pinpoint hidden items on the ground.
- There’s a Repel that isn’t hidden right near the entrance, so it’s virtually impossible to miss that.
- There’s a hidden Pearl between the third and fourth light over by the blue line.
- A valuable Nugget is in the middle of the two colored lines, right around where the fourth light is. This one is definitely worth picking up.
- There’s a Pretty Wing further south of that, again over by the blue line.
- A Repel can be found on the red line, in the same general area as the Pretty Wing.
- A Lure is out in the open for you to pick up, once again on the right side of the room, and should be hard to miss.
- A bottle of Fresh Water is shortly after the Lure, on the right line.
Two very helpful tips for searching for these hidden items:
- In this Underground Path, especially while playing Let’s Go, Eevee, it’s easiest to head all the way to the south first and then walk north to find the items. You’ll have a much easier time seeing your partner’s tail shake this way.
- Make sure you don’t have any Pokémon following you that like to walk ahead of you, such as Rattata or Bellsprout, as you might wind up interacting with them instead of picking up the items, which can waste some time.
These items will respawn every day, and sometimes an extra Nugget will be found. It’s also possible that the locations may change (needs confirmation), so just do a sweep every day to find some helpful items.
After you’ve picked up whatever you can from the Underground Path, head up the stairs and then onto Route 6 to the south.