While on the Isle of Armor, you will be given a major side quest almost immediately after arriving on the island. On you way to the Master Dojo, you will come across an Alolan Diglett hiding in the ground. A trainer will arrive and ask if you could help him find all of the Alolan Diglett hiding across the entire Isle or Armor, a whopping 150 of them to be exact. If you can do so, he will reward you for your time and effort along the way.
In order to find all 150 Diglett apart of this side quest, you will need to keep an eye toward the ground at all times to see their hair sticking out. Within the Fields of Honor, there are eighteen Diglett to be found. Within the Soothing Wetlands, there are another twenty Diglett you can find. There are another eight in the Forest of Focus, and another nine in Challenge Beach. There are seven Digletts in Brawlers' Cave, eight in Challenge Road, seven in Courageous Cavern, and seven in Loop Lagoon. Finally, there are fifteen Diglett in the Training Lowlands, three in Warm Up Tunnel, ten in Potbottom Desert, eleven in Workout Sea, seven in Stepping Stone Sea, six in Insular Sea, three in Honeycalm Sea, and eleven on Honeycalm Island.
After finding five of the Digletts, the Diglett Man will gift you with an Alolan Meowth. After finding ten, he will give you a Kantonian Slowpoke. After finding twenty and thirty Diglett, he will give you an Alolan Vulpix and an Alolan Sandshrew, respectively. After finding forty, fifty and 75 Digletts, he will give you an Alolan Raichu, an Alolan Marowak and an Alaolan Exeggutor, respectively. After finding 100 Diglett, he will gift you with either Rowlet, Litten or Popplio depending on the Starter Pokemon you originally chose in Pokemon Sword & Shield. And, of course, after finding all of the Diglett, he will give you an Alolan Diglett of your own.
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