This document will give a detailed overview of the deliverable “D1.4 Report on technical requirements for the core technology modules” for the OCEANIDS project. This deliverable is connected to Task 1.2: “Data management plan (DMP)” of Work Package (WP) 1 “Project Management”, led by Geosystems Hellas (GSH). The deliverable D1.4 is considered as one of the outputs of T1.2 more indirectly, as it is created in parallel with the DMP preparation. The former provides an analysis of the technical (functional and non-functional) and user requirements, while the latter establishes all the guidelines and directives to be followed to ensure the interoperability, both of the core technology components and the final technological and data outcomes of the OCEANIDS project. To this end, this report outlines the essential technical and end-user requirements for the development and implementation of the core technology modules, especially the technologies developed under WP3. Meeting these requirements is crucial to ensure the success and reliability of these technologies as the project moves forward.As the OCEANIDS project is currently in its first stages of implementation in M4, it is important to mention that only some preliminary discussions have been initiated in WPs monthly meetings. Therefore it was considered essential to move forward smoothly to first identify the synergies among the technological modules, and by having this information available then each partner to introduce and identify preliminary requirements for the core technology modules and platforms. The identified requirements are more basic and general, and they will better be summarised later on. It is essential to use this deliverable as a first step in identifying each Task’s responsibilities and creating the first workflow depicting the synergies that shall be established among WP3 and WP4, once the insightful information from WP2 is available and ready to use. To be in the position to set the requirements within this deliverable, input from the end-users collected under WP2 is required which is developed in parallel to identify some end-user requirements under T2.2 “Assessment of current gaps between stakeholders' needs and existing applications and services available” by exploring the needs, challenges and set priorities and goals of each partner. The time of this deliverable is not optimal, as the Engagement Plan and the interviews with the OCEANIDS stakeholders are still in progress, and will be finalised by M6. To this end, it was decided that the MS1 “Stakeholders identification and system specifications definition” (Milestone 1) in M6, will be used to provide the updated and successfully gathered information, setting the needs and requirements for the developed application, module, or platform, in collaboration with D2.1 “Stakeholders engagement plan and existing applications/services report”.Thus, the main focus of this deliverable is to provide a complete preliminary overview of the main modules and workflows developed under WP3 and the requirements from a technical perspective, but not exclusively limited to that. It is essential to maintain an integrated approach considering that the core technology modules created under WP3 will be ultimately integrated into the platforms generated under WP4. Therefore, this report will also extend to the introduction and description of WP4 platforms.