Choose a tall 15- to 20-inch glass vase to hold the coral arrangement. Pick a clear vase so that you can see the coral through it, or go with a blue glass vase to coordinate with the ocean theme.
Pick a realistic-looking plastic or glass coral branch that is at least five inches taller than the vase so that it is visible at the top. Choose a clear or white coral branch, or go with a vibrantly hued one for an eclectic look.
Fill one-quarter of the bottom of the vase with sand. Sprinkle small seashells and sea glass onto the sand to enhance the beach-inspired look.
Nestle the end of the coral branch into the sand to create a secure hold, allowing the top of the decor to protrude out of the top of the vase like a bouquet.