Guide:
Central Shadowfen, north-northeast of Alten Corimont Wayshrine, in Alten Corimont (the anchor icon).
Located in Alten Corimont, the pirate settlement. The skyshard is on the bow of the north boat. You can get on the boat via wooden platforms either from the north or the south.
Put some tune on and enjoy the view. Leo or Capt’n Flint, whatever floats your boat.