IDEATION (InlanD watErs in the digitAl Twin OceaN) is funded by the European Union’s Horizon Europe programme. IDEATION is based on a cross-border cooperation, involvement, and commitment of stakeholders at European level by following the Water-oriented Living Labs (WoLLs) approach. Stakeholders will be engaged via Multi-Stakeholder Forums (MSF), using a range of different engagement methodologies (e.g., focus groups, workshops, interviews, questionnaires) depending on goals of the engagement and specificities of the context. A comprehensive review will be performed to make an open knowledge inventory for inland water systems (OpenKIWAS). IDEATION will co-design the IDEATION reference architecture defining a set of building blocks, interfaces and standards to make data, models and technologies interoperable and integrable with the Digital Twin Ocean (DTO). Putting together all the results from the MSF, OpenKIWAS, and the IDEATION reference architecture, a roadmap for the integration of inland waters in the Digital Twin Ocean will be created providing a preliminary breakdown of the work, with priorities of implementation, into a stepped approach.