
You can only buy Timer Balls from the Poké Mart in Rustboro City. However, you first need to talk to the Devon employee on Route 116 to unlock the clerk that sells them. No other Poké Mart in the game will sell these except Rustboro’s Mart.
Alternatively, Timer Balls are also obtainable as a gift for defeating Pokémon Ranger Catherine and Pokémon Ranger Jackson in a rematch. They’re both located on Route 119.
But it’s much easier & more reliable to simply buy them from the Poké Mart once they’re unlocked.
Method #1: Rustboro City Poké Mart (Best Option)

Initially, The Rustboro Poké Mart does not sell Timer Balls. You need to unlock the clerk who sells Timer Balls, along with Repeat Balls and Net Balls.
Here’s a step-by-step on how to unlock the option to buy Timer Balls in Rustboro City’s Poké Mart:
Step 1: Start at Route 116. You can access this route by going to the northeast corner of Rustboro City.

Step 2: Head east until you reach the cave where you rescued Peeko.

Step 3: Talk to the Devon Employee, and he’ll give you a Repeat Ball.

Step 4: Head Back to Rustboro City’s Poké Mart, and a second clerk should appear. You can now buy Timer Balls from him.

Method #2: Rematch with Pokémon Ranger Catherine or Pokémon Ranger Jackson (Route 119)

One crucial function the AreaNav has is Trainer’s Eyes. Here, trainers you’ve fought before might want to challenge you to a rematch, indicated by a “Battle Ready” sign next to them.
Trainers like Pokémon Ranger Jackson and Pokémon Ranger Catherine might give you a Timer Ball when you defeat them again.
You can find both of them on Route 119. Route 119 is in between Route 118 and Fortree City. To find both Pokémon Rangers:
Step 1: Start at Route 119’s south entrance.

Step 2: Head North until you see Pokémon Ranger Catherine near the river.

Step 3: For Pokémon Ranger Jackson, head east and up the stairs.

Step 4: Cross the bridge going west.

Step 5: Head north past the tall grass until you see Pokémon Ranger Jackson.

After beating Pokémon Ranger Jackson or Pokémon Ranger Catherine in a rematch, they will have a 20% chance of giving you a Timer Ball.
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Pokémon ORAS
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