This is another route that’s divided into halves by a dungeon: the Rock Tunnel. As you come from Route 9, there’s a fairly large patch of tall grass to the right. Head over to the top-right corner of the grass to discover a Super Potion by the side of the grass.
When you’re ready, head south while following the fence towards the east. You’ll end up walking past the side of a Pokémon Centre, but before you can continue, you’ll be beset by a group of Team Rocket Grunts. Fortunately, help will arrive and you’ll only need to fight one of them.
Team Rocket Grunt
You should have fought a Raticate back on Route 9. This one is pretty much the same, but it doesn’t have Quick Attack, making it a more straightforward fight. As before, hit it with a Fighting-type if possible, but any healthy Pokémon should make mincemeat of this oversized rat.
Once the trouble’s gone, you may want to visit the Pokémon Centre to refresh your Pokémon. Or if your teammates still have stamina, feel free to carry on and defeat the remaining two trainers on this half of the route. The first trainer is standing below a bush to the south of the Pokémon Centre. He’s easily avoidable.
There’s not a lot to say about Vance’s Eevee. Smash it with Fighting-types if you want, but it’s not particularly strong. Psyduck is weak to Grass and Electric, but any Grass and Poison-types should be mildly careful of Confusion.
Past Vance, there’s 5 Poké Balls to be found in the far bottom-left corner. It can be a little hard to see because of the mountain in the way. Next, go up towards the Rock Tunnel entrance. To the left is a Coach Trainer, while to the right are 3 Great Balls in plain sight.
Coach Trainer Tasha
This trainer poses a decent challenge. Her Poliwhirl is an evolved Poliwag. Although it’s a plain Water-type, it can use the Fighting-type Brick Break, so Eevee and Normal-type users should beware. Go with Grass and Electric-types for an easy win.
Primeape is an evolved Mankey and can also use Brick Break–more effectively too since it’s actually a Fighting-type. Psychic and Fairy-types are extremely recommended. If you don’t have those, Poison and Bug-types are worth a shot, but the latter will need non-Bug moves.
Survive Tasha and she’ll gift you with TM13 Break Break. This move does decent damage and removes an opponent’s Reflect or Light Screen. If you have space in your movesets, consider learning it since it can be useful. Anyway, from here, you can enter the Rock Tunnel. But remember to heal at the Pokémon Centre first!
More or less the same Pokémon as Route 9, but with the addition of Krabby. Water-types are pretty rare at this stage, outside of Squirtle and Magikarp, and there’ll be a Fire-type Gym in the future, so feel free to catch it for your team or at least your Pokédex.