The first gym you encounter is the Violet City gym. You can only access this gym after you have defeated the Sages in the Sprout Tower. This gym features a massive wooden lift which will take you upwards to a massive platform high up shaped like the letter S. It also has a transparent border around it. On this platform, there are two trainers you can face or evade them. Once you reach the end of the platform, you will encounter the Violet City Gym Leader; Falkner

Falkner	Pidgey Lv. 9	Pidgeotto Lv. 13

Rewards:
 Zephyr Badge - Traded Pokémon up to Level 20 will obey
 TM51
 Can now use HM06 - Rock Smash in the field

After you .have removed Team Rocket from Azalea Town, you have access to the Azalea Gym. This Gym features a change in the mechanics since Gold & Silver. This time, you are faced with a chasm where there are three karts to ride on. These karts travel along webs, turning at every junction. Your task is to get onto the kart that will take you to the middle path. The other karts will take you to an area where you're confronted by a single trainer or faced with an obstacle preventing further progress. Once you reach the end of the Gym, you will encounter the Azalea Town Gym Leader; Bugsy

Bugsy	Metapod Lv. 15	Kakuna Lv. 15	Scyther Lv. 17

Rewards:
 Hive Badge - Traded Pokémon up to Level 30 will obey
 TM89
 Can now use HM01 - Cut in the field

As soon as you enter Goldenrod City, you have find that the Goldenrod Gym is locked. To gain access to it, you will need to get the Radio Card from the Radio Tower and speak to Whitney there. Once done, the gym is open. Like its appearance in the original games, the floor of the gym is shaped like a Clefairy. However, this time, the Clefairy is raised and you have to make your way around the top of it facing trainers as you go. Once you reach the end of the Gym, you will encounter the Goldenrod City Gym Leader; Whitney

Whitney	Clefairy Lv. 17	Miltank Lv. 19

Rewards:
 Plain Badge
 TM45
 Can now use HM04 - Strength in the field

As soon as you enter Ecruteak City, you will find that the Ecruteak Gym is also locked. In order to gain access to it, you need to find Morty in the Burned Tower. There with Eusine, he will talk about the Legendary Pokémon. Go to the basement and release Entei, Raikou & Suicune and Morty will go to the gym. Like its appearance in the original games, the gym requires you to go across a thin path in the dark. Unlike the previous games however, the entire gym is dark with lights only around the trainers. If you fall off of the path, you will have to restart. Once you reach the end of the Gym, you will encounter the EcruteakCity Gym Leader; Morty

Morty	Gastly Lv. 21	Haunter Lv. 21	Haunter Lv. 23	Gengar Lv. 25

Rewards:
 Fog Badge - Traded Pokémon up to Level 50 will obey
 TM30
 Can now use HM03 - Surf in the field

Heading to Cianwood City to get the SecretPotion to heal the Ampharos at the Olivine Lighthouse, you'll have immediate access to the Cianwood City Gym. Unlike the previous games, this time you have to navigate through a small maze around cliff areas in order to get the Waterfall falling on top of Chuck to stop. These valves are at the top and you have to face all trainers in order to do it. Once you reach the end of the Gym, you will encounter the Cianwood City Gym Leader; Chuck

Chuck	Primeape Lv. 29	Poliwrath Lv. 31

Rewards:
 Storm Badge
 TM01
 Can now use HM02 - Fly in the field

After you have received the SecretPotion, returned to Olivine Lighthouse and healed the Ampharos, you'll have access to the Olivine City Gym. Like the previous games, Olivine City gym is relatively sparce, featuring no extra trainers in it. Once you reach the end of the Gym, you will encounter the Olivine City Gym Leader; Jasmine

Jasmine	Magnemite Lv. 30	Magnemite Lv. 30	Steelix Lv. 35

Rewards:
 Mineral Badge - Traded Pokémon up to Level 70 will obey
 TM23

After you have defeated Team Rocket in Mahogany Town and at the Lake of Rage, you'll have access to the Mahogany Town Gym. This gym has several rooms inside it, each with various Ice Puzzles you need to navigate to get to the end, fighting trainers enroute. Once you reach the end of the Gym, you will encounter the Mahogany Town Gym Leader; Pryce

Pryce	Seel Lv. 30	Dewgong Lv. 32	Piloswine Lv. 34

Rewards:
 Glacier Badge
 TM07
 Can now use HM05 - Whirlpool in the field

After you have defeated Team Rocket in Goldenrod City and make it through the Ice Cave, you'll have access to the Blackthorn City Gym. Unlike the previous games, the Blackthorn City gym features a specific maze featuring platforms you need to move and rotate in order to get the path you desire. Once you reach the end of the Gym, you will encounter the Blackthorn City Gym Leader; Clair. However, after battling, you won't go to the badge and will have to make your way through the Dragon's Den before you can get it

Clair	Dragonair Lv. 38	Dragonair Lv. 38	Gyarados Lv. 38	Kingdra Lv. 41

Rewards:
 Rising Badge - Traded Pokémon up to Level 100 will obey
 TM59
 Can now use HM07 - Waterfall in the field

The first gym within the land of Kanto that you are likely to encounter is the Vermillion City Gym. Like the previous games, the Vermillion City gym features several bings which feature switches within them to turn off a forcefield protecting the leader Once you reach the end of the Gym, you will encounter the Vermillion City Gym Leader; Lt. Surge

Lt. Surge	Raichu Lv. 51	Electrode Lv. 47	Electrode Lv. 47	Magneton Lv. 47	Electabuzz Lv. 53

Rewards:
 Thunder Badge
 TM34

The next gym you'll find is likely to be the Saffron City gym within Saffron City. Like the previous games, the Saffron City gym features a Warp Tile puzzle where you need to find your way to Sabrina via the Warp tiles. Once you reach the end of the Gym, you will encounter the Saffron City Gym Leader; Sabrina

Sabrina	Espeon Lv. 53	Mr. Mime Lv. 53	Alakazam Lv. 55

Rewards:
 Marsh Badge
 TM48

The next gym you'll find is likely to be the Celadon City Gym. Unlike the previous games, the Celadon City gym features a pseudomaze set up by various passages with flowers growing on them. You have to navigate your way around to the gym leader. Once you reach the end of the Gym, you will encounter the CeladonCity Gym Leader; Erika

Erika	Jumpluff Lv. 51	Tangela Lv. 52	Victreebel Lv. 56	Bellossom Lv. 56

Rewards:
 RainbowBadge
 TM19

The next gym you'll find is likely to be the Cerulean City Gym. However, Misty will not be found at the gym so you'll have to go find her up at Route 25. Unlike the previous games, the Cerulean City gym features a full swimming pool with trainers you have to surf around. Alternatively, you could just walk around the edge Once you reach the end of the Gym, you will encounter the Cerulean City Gym Leader; Misty

Misty	Golduck Lv. 49	Quagsire Lv. 49	Lapras Lv. 52	Starmie Lv. 54

Rewards:
 CascadeBadge
 TM03

The next gym you'll find is likely to be the Fuchsia City Gym. Unlike the previous games, the Fuchsia City gym is run by Janine, the daughter of Koga whom you previously faced in the Elite Four. Her gym runs much like her father's did in that you have to deal with invisible walls. She also has people disguised as her so you never know whom you'll be fighting with. Once you reach the end of the Gym, you will encounter the Fuchsia City Gym Leader; Janine

Janine	Crobat Lv. 47	Weezing Lv. 44	Ariados Lv. 47	Ariados Lv. 47	Venomoth Lv. 50

Rewards:
 Soul Badge
 TM84

The next gym you'll find is likely to be the Pewter City Gym after awaking Snorlax and getting back to the West Side of Kanto. Like the previous games, there is no special puzzle to this gym. You either go straight forwards, fighting the two trainers, or go around them. Once you reach the end of the Gym, you will encounter the Pewter City Gym Leader; Brock

Brock	Graveler Lv. 51	Rhyhorn Lv. 51	Omastar Lv. 53	Onix Lv. 54	Kabutops Lv. 52

Rewards:
 Boulder Badge
 TM80

The next gym you'll find is likely to be the gym formerly on Cinnabar. As Cinnabar's volcano erupted, Blaine has moved to the Seafoam Islands. Unlike the GS games, the Seafoam Island Gym has trainers. The puzzle here requires you to beat the trainers and they will step back creating paths for you or ruining prospective ones. At the end, you will encounter the former Cinnabar Island Gym Leader; Blaine

Blaine	Magmar Lv. 54	Magcargo Lv. 54	Rapidash Lv. 59

Rewards:
 Volcano Badge
 TM50

The final gym in the game is only accessible after you have defeated the other 15 gyms go talk to Blue on Cinnabar Island and he'll leave, you will discover the Viridian City Gym is no longer empty. In it, you will encounter a puzzle featuring a variety of tiles that push you in a certain direction. Usually into another trainer. You have to find your way through the maze of paths in order to get yourself all the way over to Blue. At the end, you'll find the new Viridian City Gym Leader; Blue

Blue	Exeggutor Lv. 55	Machamp Lv. 56	Arcanine Lv. 58	Rhydon Lv. 58	Gyarados Lv. 52	Pidgeot Lv. 60

Rewards:
 Earth Badge
 TM92
 Can now use HM08 - Rock Climb in the field