For the coconut sparkling water, we used Coconut La Croix! You should be able to find that at most mainstream stores. Any sparkling coconut water will do, so use whatever you can find!
Passionfruit juice, on the other hand, can be a little tough to find at your regular grocery store! There are several options at specialty food stores, like Cost Plus World Market, and international markets.
Our favorite brands for passionfruit juice are Hawaiian Sun (great for making just a few glasses) and Ceres (perfect for making bigger batches).
As for the passionfruit juice cubes, you can usually find those at Whole Foods!