You’ll get the Rainbow Pass by giving the Ruby to Celio in the Pokémon Center / Pokémon Network Center on One Island.
The Ruby is found in Mt. Ember, which is located north of Kindle Road (just northeast of One Island.) But you can only get the Ruby after defeating the Elite Four and receiving the National Pokédex, so it’s a post-game item related closely to the Sevii Islands.
The Rainbow Pass is an end game item, so there are quite a few prerequisites to go through before you can actually obtain it and start traveling to all of the Sevii Islands.
These prerequisites are:
- Beat the Elite Four
- Obtain the National Dex (have 60+ Pokémon and talk to Oak)
- Obtain the Ruby (requires Rock Smash and Strength)
The Rainbow Pass is given to you by Celio right after delivering the Ruby to him. So obtaining the gem is the most important prerequisite.
Getting the Rainbow Pass
To get the Rainbow Pass, you need to talk to Celio on One Island (in the Network / Pokémon Center up north).
You can get to One Island via the Vermillion City port, where the S.S. Anne used to be.
When you travel to One Island and talk to Celio in the Network Center, he’ll ask you to go out and find the Ruby for him in order to upgrade his machine.
Once you find and deliver the Ruby to Celio, he’ll reward you by upgrading your Rainbow Pass.
Here’s a quick overview of where to go:
The Ruby Mission
To actually find the Ruby, you’ll want to head to Kindle Road, which is located just northeast of One Island.
So head to the east coast of the island, and then sail slightly east and slightly north.
This is Kindle Road, and we need to walk all the way to the north coast of the road.
Side Quest: Getting HM06 Rock Smash
Before heading to the northern end of Kindle Road, we should grab Rock Smash while we’re here (in case you don’t already have it).
There’s a little cave in the middle of Kindle Road that leads to a Hot Springs.
Head inside this cave and walk to the very back area, where you will find an Elderly Gentleman NPC.
Speak with him and he will give you the HM for Rock Smash, which you’ll need later on to get to the Ruby.
Tip: Keep in mind you will also need a Pokémon that can use Strength as well.
Getting to Mt. Ember
After you have Rock Smash, keep walking north on Kindle Road until you reach water. Then use Surf to sail north across the water to Mt. Ember.
Once you’re at Mt. Ember, you actually want to head to the east immediately.
Here, you will hear two Team Rocket members discussing secret plans.
Defeat both Team Rocket members and then continue into the entrance in the cave wall. You will need to make your way through the cave using Rock Smash and Strength.
Tip: We have a lengthier step-by-step guide on where to find the Ruby, so check that out if you need a more detailed walkthrough.
Once you reach the bottom of the cave, you will find yourself in a large clearing with the Ruby smack dab in the center.
Grab the Ruby, then make your way out of Mt. Ember and back to the Network Center on One Island where Celio is waiting.
Bringing the Ruby to Celio
Once you’re back on One Island, talk to Celio who is still waiting in front of his Link Machine.
Celio will upgrade your Tri Pass to a Rainbow Pass and will ask you to head out to find the Sapphire on the other Sevii Islands.
How To Use the Rainbow Pass
When you head back to the Seagallop Ferry, you will be able to select “Other” from the list of locations to travel to.
Now you can see all of the available Islands you can access with your new Rainbow Pass.