This article discusses data communication as a key to implement integrated water resource management (IWRM) in river basin management. The performance of a river basin is determined by many aspects/sectors which are managed by different level of governments and various agencies within them. Implementing IWRM requires integrated data information system provided by those various government agencies. Although it has been regulated in the Law No 17 Year 2019, integrated information system reliable to support decision-making process has not existed yet. This article reviews what is the condition of water related data in Bengawan Solo River Basin Management – the type of water related data, the data frequencies, and the data sharing mechanism. It aims to examine data communication among actors and supports the decision-making process in Bengawan Solo River Basin Management. There are three stages were undertaken to achieve this overall aim, that are 1) identifying the type of water-related data need be shared in sharing water resource from the literature; 2) identifying the availability of water-related data identified in the stage 1 in the existing data provided by government agencies; 3) conducting a series of focused group discussion (FGD) to elaborate the use of the available data to understand its limitations to support decisionmaking process. The research found that the implementation of IWRM in Bengawan Solo River Basin is difficult to be achieved because there is a lack of data communication among data providers. It points that the absence of data communication occurred because there is no definite data sharing framework specify what data need to be shared, the frequency of data collection and updating, and the mechanism in sharing data legitimated by all agencies involved in Bengawan Solo River Basin Management. Thus, it reveals that data cannot be used maximally to support effective river basin management not because of technology drawbacks or a lack of data, but its uncertainty on how data needs to be communicated. In addition, there no certainty of who is the responsible agency or authority to fulfill five aspects of data communication. This is the final homework of IWRM implementation in managing river basin in Indonesia.