Collect and organize enough sea glass for your project. Diamond bits are the perfect tool for creating small holes in the individual pieces of glass. Look for a set that will work well in a Dremel or other multi-use power tool.
It’s not often that you get the recommendation to operate power tools in the presence of water, but it’s necessary in this case. The diamond bit will get very hot as it bores through the glass, and to keep it cool, working in a shallow pool of water is ideal. The shallow pool is also great at containing glass shards and dust that are created during the process. Recycle the metal lid from a jar, and fill it with approximately 1/4” of water, or enough to submerge the sea glass.