- Like most other regions, Sinnoh also has a wide array of Gyms that trainers can battle to obtain badges and to be able to qualify for battle and face the Elite Four. The Sinnoh Gym Leaders are Roark, Gardenia, Maylene, Crasher Wake, Fantina, Byron, Candice, and Volkner. As you can see, the Gym in Eterna, Veilstone, and Hearthome were remodeled and enhanced with new features in from Diamond and Pearl to Platinum. Also in Platinum, some of the Gym Leaders have more powerful Pokémon than in Diamond/Pearl. Sometimes to get stronger in Platinum after you beat the Pokémon League, you can go to the Battle Zone where the Survival Area is to rebattle the Gym Leaders.
1st Gym - Oreburgh City[]
- Gym Leader: Roark
Oreburgh City Gym
- Specialty Type: rock
- How to access: Talk to him inside the Oreburgh Mine.
- Rewards: Coal Badge, TM76, can now use Rock Smash
| Diamond/Pearl | Platinum | ||
| Pokémon | Level | Pokémon | Level |
| Geodude | Lv. 12 | Geodude | Lv. 12 |
| Onix | Lv. 12 | Onix | Lv. 12 |
| Cranidos | Lv. 14 | Cranidos | Lv. 14 |
2nd Gym - Eterna City[]
- Gym Leader: Gardenia
D/P Eterna City Gym
Eterna City Gym (Platinum: Floral Clock)
- Specialty Type: Grass
- How to access: Meet her outside the Gym.
- Rewards: Forest Badge, TM86, can now use Cut
| Diamond/Pearl | Platinum | ||
| Pokémon | Level | Pokémon | Level |
| Cherubi | Lv. 19 | Turtwig | Lv. 20 |
| Turtwig | Lv. 19 | Cherim | Lv. 20 |
| Roserade | Lv. 22 | Roserade | Lv. 22 |
3rd Gym[]
For Diamond and Pearl[]
D/P Veilstone City Gym
Hearthome City Gym (Platinum)
- Veilstone City
- Gym Leader: Maylene
- Specialty Type: Fighting
- Rewards: Cobble Badge, can now use Fly
| Pokémon | Level |
| Meditite | Lv. 27 |
| Machoke | Lv. 27 |
| Lucario | Lv. 30 |
For Platinum[]
- Hearthome City
- Gym Leader: Fantina
- Specialty Type: Ghost
- Rewards: Relic Badge, TM65, can now use Defog
| Pokémon | Level |
| Duskull | Lv. 24 |
| Haunter | Lv. 24 |
| Mismagius | Lv. 26 |
4th Gym[]
For Diamond and Pearl[]
Pastoria City Gym
Veilston City Gym (Platinum)
- Pastoria City
- Gym Leader: Crasher Wake
- Specialty Type: Water
- Rewards: Fen Badge, can now use Defog
| Pokémon | Level |
| Gyarados | Lv. 27 |
| Quagsire | Lv. 27 |
| Floatzel | Lv. 30 |
For Platinum[]
- Veilstone City
- Gym Leader: Maylene
- Specialty Type: Fighting
- Rewards: Cobble Badge, can now use Fly
| Pokémon | Level |
| Meditite | Lv. 28 |
| Machoke | Lv. 29 |
| Lucario | Lv. 32 |
5th Gym[]
For Diamond and Pearl[]
D/P Hearthome City Gym
Pastoria City Gym (Platinum)
- Hearthome City
- Gym Leader: Fantina
- Specialty Type: Ghost
- Rewards: Relic Badge, can now use Surf
| Pokémon | Level |
| Drifblim | Lv. 32 |
| Gengar | Lv. 34 |
| Mismagius | Lv. 36 |
For Platinum[]
- Pastoria City
- Gym Leader: Crasher Wake
- Specialty Type: Water
- Rewards: Fen Badge, TM55, can now use Surf
| Pokémon | Level |
| Gyarados | Lv. 33 |
| Quagsire | Lv. 34 |
| Floatzel | Lv. 37 |
6th Gym - Canalave City[]
- Gym Leader: Byron
Canalave City Gym
- Specialty Type: Steel
- Rewards: Mine Badge, TM91, can now use Strength
| Diamond/Pearl | Platinum | ||
| Pokémon | Level | Pokémon | Level |
| Bronzor | Lv. 36 | Magnet | Lv. 37 |
| Steelix | Lv. 36 | Steelix | Lv. 38 |
| Bastiodon | Lv. 39 | Bastiodon | Lv. 41 |
7th Gym - Snowpoint City[]
- Gym Leader: Candice
Snowpoint City Gym
- Specialty Type: Ice
- Rewards: Icicle Badge, TM72, can now use Rock Climb
| Diamond/Pearl | Platinum | ||
| Pokémon | Level | Pokémon | Level |
| Snover | Lv. 38 | Sneasel | Lv. 40 |
| Sneasel | Lv. 38 | Piloswine | Lv. 40 |
| Medicham | Lv. 40 | Abomasnow | Lv. 42 |
| Abomasnow | Lv. 42 | Froslass | Lv. 44 |
8th Gym - Sunyshore City[]
- Gym Leader: Volkner
Sunyshore City Gym
- Specialty Type: Electric
- Rewards: Beacon Badge, TM57, can now use Waterfall
| Diamond/Pearl | Platinum | ||
| Pokémon | Level | Pokémon | Level |
| Raichu | Lv. 46 | Jolteon | Lv. 46 |
| Electivire | Lv. 47 | Raichu | Lv. 46 |
| Jolteon | Lv. 48 | Luxray | Lv. 48 |
| Luxray | Lv. 49 | Electivire | Lv. 50 |