Future landed missions to Europa and other ocean worlds will bring significant advances to our understanding of these environments. Such in situ exploration will enable biochemical and geophysical experiments that cannot be done from orbit and provide important new context for earlier remote sensing observations, analysis, and derived modeling. This session is intended to bring together 1) proposals for scientific experiments to be performed from the surface or subsurface of ocean worlds, 2) innovative engineering and instrument approaches to surface or subsurface exploration, and 3) landed mission concepts, such as Europa Lander. Abstracts covering mission concepts, instrument concepts and technologies, supporting laboratory work, and other novel in situ surface or subsurface science and implementation topics are encouraged, as are abstracts covering planetary protection strategies for mitigating risk of forward contamination.