Can Tera and Mega Evolution/Z-moves be used on the same Pokemon in National Dex?

Question

I don't play National Dex so I don't know. :/

Comments

You can't use Z-moves and Mega at the same time, but Tera might work.

Answer 1

You cannot Mega Evolve and Terastallize on the same Pokemon. To test this, use the following set in a battle:

test (Diancie) @ Diancite
Ability: Clear Body
Tera Type: Rock
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Diamond Storm

You cannot use a Z-Move and Terastallize on the same Pokemon, even if you have consumed your Z-Move. To test this, use this set:

test (Diancie) @ Rockium Z
Ability: Clear Body
Tera Type: Rock
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Diamond Storm

You may Terastallize if you hold an item other than a Mega Stone or Z-Crystal. Use this set:

test (Diancie) @ Leftovers
Ability: Clear Body
Tera Type: Rock
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Diamond Storm

And of course, you can't use Mega Evolution and a Z-Move on the same set. No, not even with Rayquaza. Test with:

test (Rayquaza) @ Flyinium Z
Ability: Air Lock
Tera Type: Dragon
EVs: 252 HP / 252 Spe
Jolly Nature
- Dragon Ascent

Answer 2

No. I tested this out on Showdown, and when you Mega Evolve, you cannot Terastallize. I have no idea why it doesn't work, and most obviously, you still cannot use a Z-move while Mega Evolved even in National Dex.

All of the three cannot be used simultaneously, however you can use a Z-move while Terastallized.