All of the dragons' locations are detailed on the "Overworld Map 3" in the game's "maps and guides" folder. These locations are (in no particular order):
- Mount Houzell (on a cliff in an area leading to the dungeon boss), which can't be entered without advancing the story far enough.
- Cleft of Wind (I can't recall the exact location), which can't be entered without advancing the story far enough.
- Douzmir Lake (near the broken bridge at the beginning)
- Ancient Cave/Castle, central upper castle floor outside
- Rodenia (in the northern house)
- Auslen (right basement in southwestern area)
- Frostwood Clearing
- Underworld, Torrid Grotto (at the end), which is located north of Crystalline Weald's northern exit: That's the dragon shown at Giott's Elevator on Overworld Map 3 (it's not shown on Overworld Map 4, though).