I3S is an open format for streaming massive 3D geospatial content. Adopted by Open Geospatial Consortium (OGC), the latest update, I3S OGC 1.2 brings dramatic improvements in performance and scalability. We’ll describe and demonstrate the advantages this version brings, including paged node access pattern, a more compact geometry layout, advanced material definitions property, as well as support for KTX2 compressed textures – reducing compressed texture content size by over 60%. We’ll also outline patterns for distributing I3S content thru open-source solutions such as loaders.gl and CesiumJS.