Pokemon Sun and Moon’s first island, Melemele, has quite a bit of great locations to nab yourself some good Pokemon. (Not to mention that they’re necessary if you want to fill up your Pokedex!) Ten Carat Hill is the first of these locations that you won’t necessarily need to visit, but you might want to.
In order to step foot in Ten Carat Hill, you first need to progress with the story far enough to beat the first Kahuna, Hala. He will, of course, give you the pager that lets you smash some rocks. This is what you’ve been waiting for, as Ten Carat Hill’s entrance is blocked by some boulders.
So, once you have your Tauros ride in tow, head over to the south of Melemele Island (around Route 1, where the Research Lab is) and you should see some grass to the left of your screen. Cross that, and a sign will show you that you are near Ten Carat Hill. Simply smash those rocks at the entrance, and boom, you can head inside.
Here is where you will find such pocket monsters as Rockruff, Diglett, Bonsly, and others! Not only that, but there are quite a bit of items in there, too! It’s definitely worth backtracking in this game.
For more help with Sun and Moon, be sure to check out Twinfinite’s wiki for guides and tips!