When does misty come to Hoenn?

Misty doesn't actually come to the Hoenn region in the main Pokemon anime series.

She leaves the group at the end of the Johto saga (around the end of the Pokemon Gold and Silver anime) and doesn't reappear until the beginning of the Sinnoh saga (around the beginning of the Pokemon Diamond and Pearl anime).

While there are a few instances of Misty appearing in the Hoenn anime in flashbacks or mentions, she never physically visits the region in the main storyline.