Mossdeep City is located on a small island east of continental Hoenn. Its gym leaders are Tate and Liza, and their badge is the Mind Badge.
There is a brief scene in Chapter 243, when one panel showing Marge surrounded by unconscious scientists in the Space Center takes place in Mossdeep.
- Marge knocks out the scientists at the Space Center before receiving a call from Mack asking her to join the fight against the gym leaders stopping Groudon, which she accepts
- Mossdeep City never formally debuts