How are you keeping up? We're barely a third way through, but this is another fairly easy location--compared to some of the others, anyway. This time, there are 9 Diglett, so only 1 more than the Forest of Focus. That said, there are too many places those Diglett could be hiding...
1/9: Starting from the Forest of Focus entrance, go forwards towards the rocky hill. It's hiding around the back of this hill, near some pebbles.
2/9: From Diglett 1, face the Tower of Waters. Turn right and head for the area where the shoreline ends and the raised land begins. It's sitting just below the raised land.
3/9: From Diglett 2, go up the slope towards the raised land. This one is hiding next to some pebbles after the red flowers along the left side.
4/9: From Diglett 3, continue to the end of the raised land. It's hiding in the vegetation behind the tree. Watch out for the claustrophobic camera.
5/9: Head for the Towers of Water, located at the end of the sandbar. While facing the tower entrance, go right. It's behind the rectangular slab acting as support for the tower.
6/9: Return towards the forest entrance, then travel straight ahead, until you've gone past the first bunch of tall grass. Along the left, there's some rocky terrain. Navigate around to the back of this terrain. It's hiding in the corner where the terrain meets the river, camouflaged by greenery.
7/9: From Diglett 6, with your back to the river, head for the shoreline. When you reach the shoreline, turn left and follow it to the end. Number 7 is hiding at the edge of the shore, near the grassy region.
8/9: From Diglett 7, turn so the ocean is behind you. In front of you, there should be a rocky hill. Go up to the hill and look around towards the left. It's hiding near some pebbles.
9/9: From Diglett 8, turn so the ocean is on your right. Go forward, stopping before the tall grass. Now turn left. The final Diglett is sat in-between some pebbles and greenery in front of the rocky hill that's ahead.
That makes 50+ Diglett rescued, so what prize can you expect? A good old Alolan Marowak, that's what.