Blue-Cloud 2026 presented a workshop session on the 17th of October on "Blue-Cloud Data-intensive Workbenches for selected Essential Ocean Variables (EOVs)." This session presented to the OBPS audience the Big Data Workbenches that were being developed under the umbrella of the Blue-Cloud 2026 initiative with marine data providers such as SeaDataNet, EMODnet Chemistry, CMEMS, EcoTaxa, and more. Together, utilizing best practices and standards, they worked to develop, validate, and document new analytical Big Data Workbenches, which could be adopted by EMODnet, CMEMS, and selected RIs for producing, at regular intervals, a set of harmonized and validated data collections for a selection of Essential Ocean Variables (EOVs) in physics, chemistry, and biology—highly relevant for analyzing the state of the environment and numerical simulations useful for deploying Digital Twins of the Ocean applications. The session gave a general presentation of the workflows that were being designed and implemented by ocean and data scientists from European marine infrastructures (Blue-Cloud 2026, SeaDataNet, EMODnet Chemistry, CMEMS, EcoTaxa) to deploy data-intensive Workbenches for selected Essential Ocean Variables (EOVs). Thanks to the Workbenches, researchers harmonized, validated, and qualified large and various in situ data sources, exploiting the blue analytical services available in the Blue-Cloud Virtual Research Environment. One of the first and most important steps was to analyze and select the most useful metadata to retain between several input datasets, so that they could be compared. This semantic task improved metadata used in different communities and hopefully led to a common choice. Other elements, still under development, were also showcased and presented for community feedback, such as the semantic analyzer, the semantic brokerage and the DAB components, Beacon as a powerful data lake that enabled subsetting, and how all these elements were crucial for the Workbenches.