Players can rebattle certain trainers when they activate their Vs. Seeker and the trainer is in sight. You will know the trainer is ready for a rebattle when there is an exclamation point over their head.
Once the VS Seeker is used you have to recharge it by walking 100 steps. If you try to use it and it's not charged it will tell you how many steps remain to charge it.
The VS Seeker can't be used inside forests and caves even if there are trainers there.
As you progress in the game, some trainers will have higher levelled Pokémon in their rematches.
Route 3
Lass Janice
FireRed and LeafGreen
Trainer
Pokemon
Lass Janice Reward: 320
Pidgeotto Lv. 20
Pidgeotto Lv. 20
Lass Janice Reward: 448Reach Fuchsia City and beat 1st rematch team
Pidgeotto Lv. 28
Pidgeotto Lv. 28
Bug Catcher Colton
FireRed and LeafGreen
Trainer
Pokemon
Bug Catcher Colton Reward: 228
Metapod Lv. 19
Weedle Lv. 19
Metapod Lv. 19
Bug Catcher Colton Reward: 324Reach Fuchsia City and beat 1st rematch team
Butterfree Lv. 27
Kakuna Lv. 27
Butterfree Lv. 27
Bug Catcher Colton Reward: 612Deliver Sapphire to Celio and beat 2nd rematch team
Butterfree Lv. 52
Beedrill Lv. 54
Butterfree Lv. 51
Youngster Ben
FireRed and LeafGreen
Trainer
Pokemon
Youngster Ben Reward: 272
Rattata Lv. 17
Ekans Lv. 17
Youngster Ben Reward: 448Reach Fuchsia City and beat 1st rematch team
Raticate Lv. 28
Ekans Lv. 28
Youngster Ben Reward: 768Get into the Hall of Fame
Raticate Lv. 48
Arbok Lv. 48
Route 24
Youngster Timmy
FireRed and LeafGreen
Trainer
Pokemon
Youngster Timmy Reward: 304
Raticate Lv. 19
Ekans Lv. 19
Zubat Lv. 19
Youngster Timmy Reward: 432Reach Fuchsia City and beat 1st rematch team
Raticate Lv. 27
Ekans Lv. 27
Golbat Lv. 27
Youngster Timmy Reward: 832Deliver Sapphire to Celio and beat 2nd rematch team
Raticate Lv. 52
Arbok Lv. 52
Golbat Lv. 52
Lass Reli
FireRed and LeafGreen
Trainer
Pokemon
Lass Reli Reward: 320
Pidgey Lv. 20
Nidoran♀ Lv. 20
Lass Reli Reward: 448Reach Fuchsia City and beat 1st rematch team
Pidgeotto Lv. 28
Nidorina Lv. 28
Route 25
Hiker Franklin
FireRed and LeafGreen
Trainer
Pokemon
Hiker Franklin Reward: 900Reach Celadon City
Machoke Lv. 25
Graveler Lv. 25
Picnicker Kelsey
FireRed and LeafGreen
Trainer
Pokemon
Picnicker Kelsey Reward: 360
Nidoran♂ Lv. 21
Nidoran♀ Lv. 21
Picnicker Kelsey Reward: 420Reach Fuchsia City and beat 1st rematch team
Nidorino Lv. 29
Nidorina Lv. 29
Picnicker Kelsey Reward: 980Become Champion and beat 2nd rematch team
Nidorino Lv. 49
Nidorina Lv. 49
Youngster Chad
FireRed and LeafGreen
Trainer
Pokemon
Youngster Chad Reward: 320
Ekans Lv. 20
Sandshrew Lv. 20
Youngster Chad Reward: 448Reach Fuchsia City and beat 1st rematch team
Arbok Lv. 28
Sandshrew Lv. 28
Youngster Chad Reward: 768Become Champion and beat 2nd rematch team
Arbok Lv. 48
Sandslash Lv. 48
Route 6
Camper Ricky
FireRed and LeafGreen
Trainer
Pokemon
Camper Ricky Reward: 440
Squirtle Lv. 22
Camper Ricky Reward: 600Reach Fuchsia City and beat 1st rematch team
Wartortle Lv. 30
Camper Ricky Reward: 1,100Deliver Sapphire to Celio and beat 2nd rematch team
Wartortle Lv. 55
Picnicker Isabelle
FireRed and LeafGreen
Trainer
Pokemon
Picnicker Isabelle Reward: 360
Pidgeotto Lv. 21
Pidgeotto Lv. 21
Pidgey Lv. 18
Picnicker Isabelle Reward: 520Reach Fuchsia City and beat 1st rematch team
Pidgeotto Lv. 29
Pidgeotto Lv. 29
Pidgeotto Lv. 26
Picnicker Isabelle Reward: 1,000Become Champion and beat 2nd rematch team
Pidgeotto Lv. 47
Pidgeotto Lv. 47
Pidgeot Lv. 50
Camper Jeff
FireRed and LeafGreen
Trainer
Pokemon
Camper Jeff Reward: 420
Spearow Lv. 21
Raticate Lv. 21
Camper Jeff Reward: 650Reach Fuchsia City and beat 1st rematch team
Fearow Lv. 29
Raticate Lv. 29
Camper Jeff Reward: 1,080Deliver Sapphire to Celio and beat 2nd rematch team
Fearow Lv. 54
Raticate Lv. 54
Route 11
Enginer Bernie
FireRed and LeafGreen
Trainer
Pokemon
Engineer Bernie Reward: 1344Reach Fuchsia City
Magneton Lv. 28
Magneton Lv. 28
Magneton Lv. 28
Gamer Darian
FireRed and LeafGreen
Trainer
Pokemon
Gamer Darian Reward: 2088Reach Fuchsia City
Growlithe Lv. 29
Vulpix Lv. 29
Youngster Yasu
FireRed and LeafGreen
Trainer
Pokemon
Youngster Yasu Reward: 352Reach Celadon City
Rattata Lv. 22
Raticate Lv. 22
Raticate Lv. 22
Youngster Yasu Reward: 752Become Champion and beat 1st rematch team
Raticate Lv. 47
Raticate Lv. 47
Raticate Lv. 48
Route 9
Picnicker Alicia
FireRed and LeafGreen
Trainer
Pokemon
Picnicker Alicia Reward: 500Reach Celadon City
Meowth Lv. 25
Picnicker Alicia Reward: 600Reach Fuchsia City and beat 1st rematch team
Persian Lv. 30
Picnicker Alicia Reward: 1,100Deliver Sapphire to Celio and beat 2nd rematch team
Persian Lv. 55
Hiker Jeremy
FireRed and LeafGreen
Trainer
Pokemon
Hiker Jeremy Reward: 1008Reach Fuchsia City
Machoke Lv. 30
Onix Lv. 30
Camper Chris
FireRed and LeafGreen
Trainer
Pokemon
Camper Chris Reward: 480Reach Celadon City
Growlithe Lv. 24
Charmander Lv. 24
Camper Chris Reward: 580Reach Fuchsia City and beat 1st rematch team
Growlithe Lv. 29
Charmeleon Lv. 29
Camper Chris Reward: 1,080Deliver Sapphire to Celio and beat 2nd rematch team
Arcanine Lv. 54
Charmeleon Lv. 54
Route 10 after Rock Tunnel
Hiker Trent
FireRed and LeafGreen
Trainer
Pokemon
Hiker Trent Reward: 1,116Reach Fuchsia City
Onix Lv. 31
Graveler Lv. 31
Pokemaniac Herman
FireRed and LeafGreen
Trainer
Pokemon
Pokemaniac Herman Reward: 1,392Reach Fuchsia City
Marowak Lv. 29
Slowbro Lv. 29
Pokemaniac Herman Reward: 2,593Deliver Sapphire to Celio and beat 2nd rematch team
Marowak Lv. 54
Slowbro Lv. 54
Route 8
Gamer Rich
FireRed and LeafGreen
Trainer
Pokemon
Gamer Rich Reward: 2,160Reach Fuchsia City
Growlithe Lv. 30
Vulpix Lv. 30
Super Nerd Glenn
FireRed and LeafGreen
Trainer
Pokemon
Super Nerd Glenn Reward: 672Reach Fuchsia City
Muk Lv. 28
Muk Lv. 28
Muk Lv. 28
Twins Eli & Anne
FireRed and LeafGreen
Trainer
Pokemon
Twins Eli & Anne Reward: 672Reach Fuchsia City
Clefairy Lv. 28
Jigglypuff Lv. 28
Lass Megan
FireRed and LeafGreen
Trainer
Pokemon
Lass Megan Reward: 352Reach Cledan City
Pidgeotto Lv. 22
Raticate Lv. 22
Nidoran♂ Lv. 23
Meowth Lv. 21
Pikachu Lv. 22
Lass Megan Reward: 768Become Champion and beat 1st rematch team
Pidgeot Lv. 46
Raticate Lv. 47
Nidorino Lv. 47
Persian Lv. 47
Raichu Lv. 48
Biker Jaren
FireRed and LeafGreen
Trainer
Pokemon
Biker Jaren Reward: 600Reach Fuchsia City
Muk Lv. 28
Muk Lv. 30
Route 12
Fisherman Elliot
FireRed and LeafGreen
Trainer
Pokemon
Fisherman Elliot Reward: 1,008Reach Fuchsia City
Poliwhirl Lv. 28
Cloyster Lv. 28
Seaking Lv. 28
Seadra Lv. 28
Young Couple Gia & Jes
FireRed and LeafGreen
Trainer
Pokemon
Young Couple Gia & Jes Reward: 1680Reach Fuchsia City
Nidorino Lv. 30
Nidorina Lv. 30
Young Couple Gia & Jes Reward: 3080Deliver Sapphire to Celio and beat 1st rematch team
Nidoking Lv. 55
Nidoqueen Lv. 55
Rocker Luca
FireRed and LeafGreen
Trainer
Pokemon
Rocker Luca Reward: 792Reach Fuchsia City
Electrode Lv. 33
Electrode Lv. 33
Route 13
Picnicker Susie
FireRed and LeafGreen
Trainer
Pokemon
Picnicker Susie Reward: 540Reach Fuchsia City
Pidgeotto Lv. 27
Meowth Lv. 27
Raticate Lv. 27
Pikachu Lv. 27
Meowth Lv. 27
Picnicker Susie Reward: 940Become Champion and beat 1st rematch team
Pidgeotto Lv. 47
Persian Lv. 47
Raticate Lv. 47
Pikachu Lv. 47
Persian Lv. 47
Picnicker Susie Reward: 1,040Deliver Sapphire to Celio and beat 2nd rematch team
Pidgeot Lv. 52
Persian Lv. 52
Raticate Lv. 52
Raichu Lv. 52
Persian Lv. 52
Beauty Sheila
FireRed and LeafGreen
Trainer
Pokemon
Beauty Sheila Reward: 3,528Become Champion
Clefairy Lv. 49
Persian Lv. 49
Bird Keeper Robert
FireRed and LeafGreen
Trainer
Pokemon
Bird Keeper Robert Reward: 672Reach Fuchsia City
Pidgeotto Lv. 28
Pidgeotto Lv. 28
Fearow Lv. 28
Fearow Lv. 28
Bird Keeper Robert Reward: 1,128Become Champion and beat 1st rematch team
Pidgeot Lv. 47
Pidgeot Lv. 47
Fearow Lv. 47
Fearow Lv. 47