Dataspaces have emerged as ecosystems that facilitate seamless and trusted data sharing, and they have recently attracted growing interest from policymakers, researchers, and practitioners alike. This rising attention is driven in part by regulatory developments such as the European Data Governance Act (DGA), which has boosted the visibility and relevance of dataspaces, particularly, though not exclusively, in Europe. The DGA defines terms such as data and service providers, and is a regulation aimed at promoting fair and equitable data use and establishing a framework for data governance within the EU. Moreover, it aims to increase trust in data sharing, expand the availability of data for reuse, encourage the development of common dataspaces, and promote the use of data for good. The DGA will impact various sectors, including data providers, researchers, businesses and citizens. Other examples include the movement to establish national and international research data management infrastructures, such as the European Open Science Cloud, the NFDI, and others. The growing adoption of the FAIR Data Principles, originally introduced by the semantics community, is playing a key role in shaping the development of national and international dataspaces. These principles, which emphasize that data should be Findable, Accessible, Interoperable, and Reusable, align closely with the objectives of dataspaces to enable efective and trustworthy cross-organizational data sharing. For example, the European Union is investing between 4 and 6 billion euros to establish sector-specific dataspaces and has explicitly required that they adhere to the FAIR Principles. Implementing these principles at scale, however, demands more than policy. It requires robust technical foundations, particularly in the area of semantic interoperability. This is where the Semantic Web community can ofer critical expertise, drawing on decades of experience in developing RDF-based standards and solutions. As such, dataspaces
represent a significant and timely opportunity for the Semantic Web community, with the potential to drive innovation across a wide range of application domains.
The Semantics in Dataspaces (SDS) workshop series aims to foster collaborative eforts to develop semantic methods and solutions tailored for dataspaces. The workshop series focuses on improving the expressiveness and standardization of semantic methods and solutions for dataspaces, facilitate the development of shared semantic resources for dataspaces, explore the integration of semantic technologies into dataspace architectures, and promote the adoption of semantic approaches in dataspace implementations. The SDS workshop also serves as a platform to bring together a diverse community of researchers and practitioners in this area. It is highly interactive and communicative, with formal presentations as well as extensive discussions. Especially through engaging discussions and collaborative eforts, the workshop aims to advance the state of the art for semantics in dataspaces.
The Third International Workshop on Semantics in Dataspaces continues the success of its previous
editions [
The topics of interest in this workshop are threefold: First, a conceptual perspective highlights definitions of dataspaces, their core elements, and lifecycles. Participants examine formal models, the impact and potential of unique identifiers, and conceptual reusable assets in general. Second, stateof-the-art implementations in both academia and adoption are reviewed. This includes comparisons of current dataspace eforts and analyses of their requirements, key drivers, and common sustainable elements and standards. Last but not least, this workshop especially focuses on advancing the application of semantics for dataspaces. Participants evaluate the potential of semantic-based methods and solutions for dataspaces, and discuss the tailored benefits of ontologies and semantic models, unique identifiers, algorithms, the role of artificial intelligence and large language models, and concepts for a widespread dataspace adoption in the future.
With more than a dozen contributions and around thirty participants, the third SDS workshop presented many challenges, but also opportunities that will enhance the potential of dataspaces and lead to future global solutions. As workshop organizers, we are excited to strengthen the role of semantics for dataspaces and are confident that this workshop provided a stimulating and engaging forum for researchers and practitioners working in this area.
In this workshop edition, 19 papers were submitted for peer review. Of these, 13 papers were accepted
for this volume, 4 as regular papers and 9 as short papers:
• Ontology-Driven eMobility Booking Management in the Energy Data Space [
DAPS [
Analysis [13] • The Synergy of Large Language Models and Dataspaces - A Functional Exploration [14] • Exploring Human Usability Challenges in Dataspaces [15] • Representing Knowledge in Dataspaces [16]
The SDS chairs would like to thank all authors for submitting their papers, the members of the program committee for their thorough and detailed reviews, the presenters for their exciting talks, and the numerous participants for the great discussions during the workshop. In the open discussion session, the participants again confirmed to use the term dataspace in one word instead of data space. This emphasizes the role of dataspaces as a concept and research area, rather than just a space with data, similar to how database was coined earlier. During this discussion session, participants also discussed the dataspace challenges1, which have been created and discussed by members of the W3C Dataspaces Community Group2 since the last workshop edition. The formed consensus and joint decisions on these challenges will soon be reflected on the respective issues on GitHub and thus enable a clear, continuous collaboration on relevant topics in the scope of dataspaces. The discussed GitHub issues include: Pipelining workflows across participants, data discovery, interoperable policy engines, end-user confidence in data integrity, actual semantics in dataspaces, the scope of the community group, representing knowledge in dataspaces, conceptual relation between dataspace components, federated vocabulary hubs, and the handling of use cases.
Program Committee (Alphabetical Order)
[13] X. Wang, T. Käfer, Towards Semantics and Protocols for Contract Conclusion via the Web Architecture - A Gap Analysis, in: The Third International Workshop on Semantics in Dataspaces, co-located with the Extended Semantic Web Conference, June 01 – 02, 2025, Portorož, Slovenia, CEUR-WS, 2025. [14] S. Chmielewski, T. Meisen, A. Pomp, The Synergy of Large Language Models and Dataspaces - A Functional Exploration, in: The Third International Workshop on Semantics in Dataspaces, co-located with the Extended Semantic Web Conference, June 01 – 02, 2025, Portorož, Slovenia, CEUR-WS, 2025. [15] J. F. Ingles-Romero, M. Ferri, A. Jara, Exploring Human Usability Challenges in Dataspaces, in: The Third International Workshop on Semantics in Dataspaces, co-located with the Extended Semantic Web Conference, June 01 – 02, 2025, Portorož, Slovenia, CEUR-WS, 2025. [16] P. Moosmann, R. Deshmukh, C. Lange, J. Theissen-Lipp, Representing Knowledge in Dataspaces, in: The Third International Workshop on Semantics in Dataspaces, co-located with the Extended Semantic Web Conference, June 01 – 02, 2025, Portorož, Slovenia, CEUR-WS, 2025.