Glass sponges are deep sea marine animals. There are no records of this group of sponges being found in freshwater.
Glass sponges occur worldwide, predominantly at depths between 10 and 1000 metres (20 -3,300 feet). Although they are more abundant and diverse in shallower depths of polar regions.
Species are found in the deep Southern Pacific around the coast of Japan and Philippines and more recently new species have been found off Australia.
Species are the oldest multi-cellular animals found in the fossil record. Spicules have been found in Mongolia and China which have been dated to the Late Proterozoic (2500 to 542.0 ± 1.0 million years ago). The Hexactinellida are thought to have reached their maximum diversity during the Cretaceous (99.6 – 65.5 million years ago), when these sponges formed the vast reefs of the Tethys Sea. These reefs can now be found as stony outcrops from southern Spain through France, Germany, and Poland all the way to Romania.