Preface The NatureHCI workshop brought together researchers interested in the role of technology in shaping the experience of the natural environment, broadly intended as an open-air setting that includes cities, peripheries, rural areas, wild natural environment, etc. Resonating with the CHItaly theme "Frontiers of HCI", the workshop explored the frontiers of i) using technology outdoors in terms of scope, opportunities, and limitations; ii) spaces that are not completely natural nor artificial but hybrid and offer opportunities for remote and asynchronous outdoor experiences; iii) interaction design in accounting for human interests over a variety of non- human ecologies. Through these topics, we wanted to question how the different aspects of nature are treated in HCI research and start a conversation capable of renovating HCI discourses and practices about nature. Papers have been gathered through a call issued in Spring 2021. We received 8 submissions from different parts of the world, including France, Germany, Turkey, the U.S.A, and Italy. We employed a double-blind peer-review process involving scholars of various fields related to Human-Computer Interaction as reviewers. At the end of the reviewing process, all 8 papers were accepted. Workshop chairs • Eleonora Mencarini, i3 research unit, Fondazione Bruno Kessler, Italy • Amon Rapp, Dept. of Computer Science, University of Torino, Italy • Linda Tonolli, Dept. of Information Engineering and Computer Science, University of Trento, Italy • Maurizio Teli, Dept. of Planning, Aalborg University, Denmark • Roberto Cibin, Dept. of Information and Library Studies, Masaryk University, Czech Republic • Vincenzo D’Andrea, Dept. of Information Engineering and Computer Science, University of Trento, Italy • Massimo Zancanaro, Dept. of Psychology and Cognitive Science, University of Trento, Italy Reviewers of the workshop papers • Gabriela Avram, University of Limerick, Ireland • Ahmet Börütecene, Linköping University, Department of Science and Technology • Ashley Colley, University of Lapland, Finland • Bronwyn Cumbo, Monash University, Australia • Florian Daiber, DFKI, Germany • Felix Kosmalla, DFKI, Germany • Paolo Massa, FBK, Italy • Laura Maye, University of Cork, Ireland Copyright © 2021 for the individual papers by the papers' authors. Copyright © 2021 for the volume as a collection by its editors. This volume and its papers are published under the Creative Commons License Attribution 4.0 International (CC BY 4.0).