you go to the sea-foam islands it's on the second floor
on cinnabar island
by beating the gym leader
Talk to Blue on Cinnabar Island.
He is in the cave on Seafoam Island, which is east from Cinnabar.
The seventh gym (Blaine's) used to be on Cinnabar Island. After the town was destroyed by the volcano, Blaine has relocated his gym to the Seafoam Islands. Just Surf east of Cinnabar, and you will reach him.
Go east of Cinnabar Island to the Seafoam Islands, the gym leader is there using a cave for his gym.
Talk 2 blue at cinnabar island then go 2 the Viridian city gym.
to battle Blue in Pokemon Heartgold you must defeat the 7th gym leader, then find him on cinnabar island. Talk to him, then he will go back to his gym for you to fight
At the Seafoam Islands because of the volcanic eruption on Cinnabar Island.
Well after you defeat 15 gym leaders in Pokemon HeartGold / SoulSilver go to Cinnabar Island and talk to Blue.
the easiest way to get there is to go to pallet town and go south using surf. if you looking for that gym look at the seafoam islands instead of cinnabar because cinnabar got destroyed by the volcano on the island
Blue is on Cinnabar Island. But to be able to fight him, you must find Blaine the old Cinnabar gym leader. He is in the seafoam islands. Beat him, and then talk to Blue again. He will then return to his gym, where you can fight him!