Hydrodiplomacy is the emerging framework where legal acts, based on technical data and information, aim to support commonly accepted solutions to water-related tensions among states with transboundary waters. In this research, hydrodiplomacy components in relation to (a) policy, (b) preventive, (c) cooperative, and (d) technical aspects are considered together with climate change, which is bound to destabilize the core element of hydrodiplomacy, i.e., water. The study area is composed of the five transboundary river basins of Greece. The coupling of all these different nature elements is conducted with the use of the AHP multicriteria method, and the results of a normalized output that quantifies water transboundary cooperation in the climate crisis era are given.