How to Catch Necrozma
Necrozma can be caught after completing all the quests relating to Ultra Beasts.
【How to Catch Necrozma】
Location: Ten Carat Hill
You will have to complete the main storyline and catch all 7 Ultra Beasts to receive a reward from Looker. After you have completed these tasks, enter Ten Carat Hill which is located southeast of Hau’oli City. Ride on your Tauros to destroy the rocks blocking your path, and head towards the open area where you will find tall grasses.
Once you reach the open area, Necrozma will appear in the tall grass located at the top left corner.
The hardest Pokemon in the Game to Catch
Necrozma’s level is Lv.75 which is very high for a wild Pokemon. It would be wise to bring the strongest Pokemons you have when trying to catch it. A Pokemon that can use False Swipe or Sleep Power would be perfect.
If you have not used your Master Ball yet, now would be the perfect opportunity to use it.