Pokemon Sun and Moon

Sun Versus Moon

 - The two games are literally day and night, but the differences aren't quite so.

The two games are literally day and night, but the differences aren't quite so.

 - The two games are literally day and night, but the differences aren't quite so.

The two games are literally day and night, but the differences aren't quite so.

 - The two games are literally day and night, but the differences aren't quite so.

The two games are literally day and night, but the differences aren't quite so.

 - The two games are literally day and night, but the differences aren't quite so.

The two games are literally day and night, but the differences aren't quite so.

The mainline Pokémon games generally arrive in pairs and this time it's no different. As usual, it doesn't matter too much which game you pick--Sun or Moon--as the game itself is essentially the same. The main difference lies in the Pokémon you can catch, although there is a bit more to it than that...

Time Offset

Actually, the biggest difference between Sun and Moon can be felt as soon as you start the game. If you're playing Pokémon Sun, you won't notice a thing. However, Pokémon Moon players will discover the time of day in the game has been shifted by 12 hours.

What this means is that if it's day time in real life, it will probably be night time in Pokémon Moon and vice versa. The in-game time is determined by the 3DS clock, so if you don't fancy the time asymmetry, you can set your clock back or forth 12 hours. Just be wary of possible side effects in other games!

Exclusive Pokémon

The other big difference--and one you can't reliably control--is the Pokémon species that you can only catch in one version or the other. If you're a Sun player and you want a Pokémon exclusive to Moon (or vice versa), you'll need to trade with somebody or you're out of luck.

New Pokémon

Exclusive to Sun Exclusive to Moon
Passimian Oranguru
Turtonator Drampa
Vulpix (Alolan) Sandshew (Alolan)
Ninetales (Alolan) Sandslash (Alolan)
Solgaleo Lunala
Buzzwole Pheromosa
Kartana Celesteela

Returning Pokémon

Exclusive to Sun Exclusive to Moon
Cottonee Petilil
Whimsicott Lilligant
Rufflet Vullaby
Braviary Mandibuzz
Cranidos Shieldon
Rampardo Bastiodon
Tirtouga Archen
Carracosta Archeops

Exclusive Evolution

Related to the above, Rockruff can evolve into one of two forms, depending on which game you're playing. Those playing Sun can witness Rockruff evolving into Lycanroc (Midday), while those with Moon will end up with Lycanroc (Midnight) instead.

Likewise, if you like the look of the other Lycanroc, you can trade with somebody who's got the game that you don't own. Or if you really want your own Rockruff to evolve into the other form, you could temporarily loan the Rockruff and have it evolve in the other game, before taking it back.

There's one more Pokémon that evolves into one of two Pokémon depending on the game, but we'll keep quiet due to story spoilers.

Alternate Events

Without spoiling too much, some of the events that occur during the story can vary depending on if you're playing Sun or Moon. For instance, the Totem Pokémon you encounter at the end of a trial may be different or you may be forced to fight a different kind of Ultra Beast.