From Zelda Wiki.org
Headstone Island is the entrance to the
Earth Temple in
The Legend of Zelda: The Wind Waker, but is blocked by a giant, headshaped stone that you can't blow up. The only way you can move it is to get the
Power Bracelets at
Fire Mountain and get the
Earth Sage. Once you have those two, you may enter.
See Also
Great Sea Islands