Question

What legendary Pokemon are obtainable in ultra sun/ultra moon but their shiny formes are unobtainable in game?

Comments

Do Mythicals count?

Answer 1

Shiny Legendary Pokémon that cannot be obtained in-game:

• Cosmog
• Cosmoem
• Tapu Bulu
• Tapu Fini
• Solgaleo
• Lunala
• Necrozma
• Tapu Koko
• Tapu Lele

Shiny Mythical Pokémon that cannot be obtained in-game:

• Magearna

Source

Comments

The Tapu(s) are legendaries, not pseudo Legendaries. And the asker only wanted to know about unobtainable shiny legends, not mythicals too. Marshadow and Zeraora are unobtainable in all ways because their events are over so they shouldn't be in this answer. Tapu Koko should be added to this answer because it's shiny was an event that's now over. Also make sure Tapu Lele stays in this answer because it's an event too.

---

Tapu Lele, Bulu, and Fini are shiny locked, only Tapu Koko is available. So the list is fine.

---

Sorry for the misunderstanding, but I meant that could not be obtained by event either.

---

So... Does this mean, I'm wrong? Preposterous!

---

So... Tapu Koko and Lele are considered "obtainable"?

Answer 2

Tapu Bulu, Tapu Fini, Cosmog, Cosmoem, Solgaleo, Lunala, Necrozma
source
source

Comments

Tapu Koko should be added to this answer because it's shiny was an event that's now over. Also add Tapu Lele to this answer because it's an event too.

---

But they are still able to be obtained in game. You don't find them there, but they are able to be shiny. :P

---

It may have been/be possible to get their shinies but that doesn't mean EVERYONE can get them naturally in game. Anyone who doesn't get the event(s) it becomes like the event(s) never existed for them. That's why I think Tapu Koko and Lele should be here.