OK I love these boots, they are lined all the way through with ugg shearling, I personally never wear socks with my uggs so I did not size up, I wouldn't recommend sizing up either. Once the shearling is pressed into place they are perfect, honestly I would say they are true to size. My feet stay incredibly warm and I can even wear them up to the mountain. I get tons of complements on them, just a really great boot to have all around, great quality.
