How do you get to spear pillar?

If you want to retrieve dialga or palkia, start from orebourgh city then go up from the sand dunes and go right, and there is a cave inside

Hope this helped

To get to the spear pillar, you need to get to the top of Mount Coronet. I always start from the Orebourgh City side. You'll need rock smash, rock climb, strength, and surf.