As knowledge around bio-digital interaction continues to unfold, there are new opportunities for HCI researchers to integrate biology as a design and computational material. Our motivation for the workshop is to bring together interdisciplinary researchers with interest in exploring the next generation of biological HCI and exploring novel bio-digital interfaces implicating diverse contexts, scales, and stakeholders. The workshop aims to provide a space for interactive discussions, presentations, and brainstorming regarding opportunities and approaches for HCI around bio-digital interfaces. We invite researchers from both academia and industry to submit a short position paper in the following areas: Synthetic Biology, Biological Circuits, Do-It-Yourself Biology (DIYBio), Biomimetic Interfaces, Living Interfaces, Living Artefacts, and Bio-ethics. We will evaluate submissions on fit, ability to stimulate discussion, and contribution to HCI. On our website we have included examples of past work in this area to help inspire and inform position papers. Our website will host a recording of the entire workshop session with accepted papers to support asynchronous viewing for participants who are unable to attend in-person or synchronously.