Start at Loriasel Wayshrine and head southwest. Pass by Xal Ithix and further ahead you will see two wooden bridges, one behind the other, connecting two peninsulas. It’s an oval road east of Xal Ithix on the map. You will have to climb up the southern peninsula and pass through the cave. Cross the bridge, go left, cross the second bridge, follow the path turning east, and voilà! You are in front of a stone shrine. The skyshard is located on the eastern side of the shrine.
View of the first wooden bridge, you can see a light at the cave exit and the skyshard on the top of the hill.
The second wooden bridge. The first one is seen on the left and the shrine is ahead.
Next to the base of the shrine.