You can only battle Hearthome City's gym leader Fantina after you have defeated Pastoria City's gym leader, Crasher Wake.
crasher wake is the gym leader after beating you get to use defog outside of battle
The gym leader of Hearthome City is Fantina. When the player first arrives at the city, she will not be in her gym. She can only be battled after the player deliver the Old Charm to the elder at Celestic Town.
It is Crasher Wake, in Patoria City.
Crasher Wake is in Pastoria City.
You have to defeat gym leader Maylene of Veilstone city (fighting type) and gym leader Crasher Wake of Pastoria city (water type).
After beating the third Gym Leader (Maylene the Veilstone Gym Leader) in Pokémon Diamond, you then head to Pastoria City to battle the Gym Leader there who is named Crasher Wake.
Pastoria city
She should be back at her Gym in Hearthome now, since she's the fifth Gym leader and all.
after getting the Pokemon flute go west of celadon city and wake up snorlax and then head south to fuschia city which is where the 5th gym leader is.
Here is the full list.Gym Leader 1: Roark: Oreburgh City Gym Leader. >HM: Rock smashGym Leader 2: Gardenia: Eterna City Gym Leader. >HM: CutGym Leader 3: Maylene: Veilstone City Gym Leader. >HM: FlyGym Leader 4: Crasher Wake: Pastoria City Gym Leader.>HM: FogGym Leader 5: Fantina: Hearthome City Gym Leader. >HM: SurfGym Leader 6: Byron: Canalave City Gym Leader.>HM: StrengthGym Leader 7: Candice: Snowpoint City Gym Leader>HM: Rock ClimbGym Leader 8: Volkner: Sunyshore City Gym Leader >HM: Warterfall
pastoria city. his name is crasher wake