When the player helps the Diglett Trainer find at least 100 Alolan Diglett, the player can gets one of the Alolan Starters as a gift.
The Alolan starter the player receives matches the type of the starter they receive at the start of their journey.
This marks the first time the Alolan Starters can be obtained in Sword and Shield.
(This statement above excludes any kind of transfer via Pokémon HOME)
This gift cannot be shiny.