- Main article: Red Moon
In Final Fantasy IV, there are two moons, one of which is the Red Moon, is an important location. It is actually an artificial structure, and home to the Lunarians, the race to which Kluya, father of Cecil and Golbez, belongs. Cecil, after losing all the Crystals to Golbez, goes to the Moon via the Lunar Whale—a ship made by Kluya—that allows one to travel through space. The Red Moon is also home to the God of Eidolons, Bahamut, and the Hummingway tribe.
In Final Fantasy IV: The After Years, a new moon appears in the sky. It is home to the Creator, an entity that travels the cosmos using his moon, observing planets as their inhabitants evolve and judging whether they are deserving of living and destroying the same planets with this moon in case they are not.
- Main article: Black Moon
- Main article: Moon (Final Fantasy VIII)
In Final Fantasy VIII, the Moon is the true origin of the monsters, and the reason why these infest the planet. The event where monsters are brought into the planet is called the Lunar Cry.
- Main article: Twin Moons (Final Fantasy IX)
The planet of Gaia has two moons, one red, which actually originates from Terra, and its original blue moon. The moons do not play a part in the storyline, but there is a Tetra Master card dedicated to them.
As Vana'diel's moon orbits the planet it passes through distinct lunar phases, moving from the New Moon to the Full Moon and back again through cycles of waxing and waning. One full lunar cycle lasts for 84 in-game days, which translates to 3 days, 8 hours, 38 minutes, and 24 seconds of Earth time. Interestingly, the moon's color varies based on the current day of the Vana'diel week. For example, the moon will appear red on Firesday, but the next night on Earthsday it will take on a yellow hue.
The moon's phase is known to affect certain aspects of the game. For instance, some Notorious Monsters such as Haty and White Coney will only spawn during a Full Moon, but others such as Bendigeit Vran and Black Coney only appear during a New Moon. An Ark Pentasphere, required for the "Divine Might" quest, can only be obtained during a Full Moon, whereas the quest "Searching for the Right Words" cannot be completed during a New Moon. Various pieces of equipment in the game also provide the player with additional, beneficial effects depending on the moon phase.
In addition to these effects, many players believe the moon phase to influence several other aspects of the game. The Full Moon is thought to increase the drop rate of loot found on monsters, cause plants grown through gardening to yield better results, and improve the overall success rate of synthesizing items through crafting. Conversely, drop rates seem to be slightly worse as it approaches the New Moon, and crafting is more likely to fail but instead provides a greater chance of skill-ups and high-quality synthesis results. Fishing results seem to be best on the Full Moon and the New Moon, with results deteriorating slightly as it approaches the Quarter Moon.
In Abyssea, an alternate dimension that exists parallel to Vana'diel, the moon seen in the night sky appears significantly larger than the one found in Vana'diel. As the player progresses through the storyline, it is revealed that the Abyssean version of Al'Taieu no longer hangs in a paradox state above the planet, but instead of returning to Qufim Island it has ascended to the moon for unknown reasons. After defending the nine Abyssean zones from the fiends that threaten them and defeating the six Caturae, the player is able to access Abyssea - Empyreal Paradox. It is here, high above the moon and the Celestial Capital of Al'Taieu that they challenge Shinryu, the final boss of the Abyssean storyline.
- Main article: Dalamud
Eorzea was initially orbited by two moons, a large white moon and a lesser red moon named Dalamud. The larger moon is said to be represented by the goddess Menphina, and Dalamud was known as "Menphina's loyal hound" due to its orbital characteristics. The events of the Seventh Umbral Calamity brought Dalamud down unto Eorzea, where it was revealed to be of artificial origin.
In A Realm Reborn, only the larger moon remains in orbit. It progresses through lunar phases as Eorzean days pass.
- Main article: Crimson Moon
In Final Fantasy Crystal Chronicles: Ring of Fates, the Crimson moon is a manifestation of pure evil created long ago when the God of Light created the planet. When he created the world, he extracted its chaotic evil in the form of a moon. Humans who are influenced by its power become Lunites.
A natural satellite, or moon, is a celestial body that orbits another body, e.g. a planet, which is called its primary.