Sawk is only obtainable in Black, White, Black 2, White 2, Dream World, X, Y, Alpha Sapphire, and Sword and Shield
Throh is only obtainable in Black, White, Black 2, White 2, Dream World, X, Y, Omega Ruby, and Sword and Shield.
In order to obtain Sawk and Throh in Gen 7 games (Sun, Moon, Ultra Sun, and Ultra Moon), you’d need to trade with someone else, or transfer from a previous game. Unfortunately, trading on the GTS or online isn’t easily assessable since online connectivity has been shut down for the Nintendo 3/DS families. However, you will be able to trade locally if you know anyone in-person who has a Sawk/Throh in their Ultra/Sun/Moon.
If you have any Gen 5 games, such as Black/White/2, you could catch them in those games, and transport them using the PokeTransporter, assuming you have it downloaded on your console.
If you have a Gen 6 game, like X, Y, Alpha Sapphire or Omega Ruby, you could use Pokemon Bank to move the Pokemon from those games to Sun and Moon, assuming you have Pokemon Bank installed.
Despite Sawk and Throh being obtainable in Sword and Shield, you cannot catch them in those games to send to Gen 7.
TL;DR it is possible, but it will be complicated, as it would require another game, trading, or external software/services.
Hope this helps!
