Below is a guide on the locations of the 6 Digletts in Insular Sea.
1. Located on a large island in the sand
2. On the same island as the above Diglett in a red flower patch next to a berry tree
3. From the previous Diglett look towards the large tree on the island. Take the left path around the tall grass to find a Diglett in the grass near the tree and a patch of red flowers.
4., 5. & 6. On a small island with a den. When you interact with one of the two Digletts that are there, a third will just show up!
