Route 10 leads to Rock Tunnel. The tall grass in this route contains one of the very few electric-type Pokémon available so far in the game.
It's useful to have picked up HM05 Flash from one of Professor Oak's aides in Route 2, accessible through Diglet's Cave, before going into Rock Tunnel, as it's a dark tunnel, the only in the game like this. Going through Rock Tunnel is the only way to progress at this point, as there is a Snorlax blocking Route 12 and a thirsty guard blocking Saffron City's gate.
Inside the Pokémon Center near Rock Tunnel is another of Professor Oak's aides. If you have complete data on 20 different species of Pokémon, they will reward you with an Everstone, an item to be held by a Pokémon that prevents it from evolving. Obscurely, Pokémon may learn certain different moves by delaying evolution, although normally it's not needed at all.
You will leave this route leaving behind a water path left to be explored at a later point, by backtracing.
Pokémon found
| FireRed | Level | Encounter Rate | LeafGreen | Level | Encounter Rate |
|---|---|---|---|---|---|
 Voltorb
|
14-17 | 40% | Voltorb
|
14-17 | 40% |
 Spearow
|
13-17 | 35% | Spearow
|
13-17 | 35% |
 Ekans
|
11-17 | 25% |  Sandshrew
|
11-17 | 25% |
Trainers
| Name | 1st | 2nd | Money | |
|---|---|---|---|---|
| 1 |  Heidi
|
 Pikachu 20
|
 Clefairy 20
|
 400
|
| Name | 1st | 2nd | Money | |
|---|---|---|---|---|
| 1 |  Mark
|
 Rhyhorn 29
|
 Lickitung 29
|
1392
|
| Name | 1st | 2nd | Money | |
|---|---|---|---|---|
| 1 | Carol
|
 Pidgey 21
|
 Pidgeotto 21
|
420
|
| 2 |  Clark
|
 Geodude 21
|
 Onix 21
|
756
|
| 3 | Trent
|
Onix 19
|
 Graveler 19
|
684
|
| 4 | Herman
|
 Cubone 20
|
 Slowpoke 20
|
960
|
Items
- Everstone (Given to you by one of Professor Oak's aides in the Pokémon Center for having owned at least 20 different species of Pokémon)
- Super Potion (Hidden just west of the Pokémon Center, accessible by using Cut on a tree)
- Persim Berry (Visibly hidden in the southeast fence corner of the Pokémon Center area)
- Cheri Berry (Visibly hidden a few spaces west, behind Picnicker Heidi, near the Pokémon Center)
- Nanab Berry (Visibly hidden in the northeastern corner, exiting out of Rock Tunnel's southern entrance)
- Max Ether (Hidden in a southern part of the route, near the Power Plant)
New Pokémon
Other than Pikachu in Viridian Forest, this is the only electric-type Pokémon you'll see until you can visit the Power Plant. Voltorb's only offensive electric move is Spark, at level 21, so it needs to be taught some moves to get better. It's a good idea to pick up a TM from the Rocket Game Corner in Celadon City if you plan on making Voltorb your primary electric-type. Voltorb evolves into Electrode starting at level 30.