BackgroundAvailable resources within an organization can determine the implementation success of an intervention. However, few studies have investigated how the required resources change over the phases of implementation. Using stakeholder interviews, we examined the changes in and interactions between available resources and implementation climate in the implementation and sustainment phases of a national implementation effort for a population health tool.MethodsWe conducted a secondary analysis of the interviews with 20 anticoagulation professionals at 17 clinical sites in the Veterans Health Administration health system about their experiences with a population health dashboard for anticoagulant management. Interview transcripts were coded using constructs from the Consolidated Framework for Implementation Research (CFIR) and according to the phase of implementation (pre-implementation, implementation, and sustainment) as defined by the VA Quality Enhancement Research Initiative (QUERI) Roadmap. We analyzed the factors that may determine successful implementation by examining the co-occurrence patterns betweenavailable resourcesandimplementation climateacross different implementation phases. To illustrate the variations in these determinants across phases, we aggregated and scored coded statements using a previously published CFIR scoring system (− 2 to + 2). Key relationships betweenavailable resourcesandimplementation climatewere identified and summarized using thematic analysis.ResultsThe resources necessary to support the successful implementation of an intervention are not static; both the quantity and types of resources shift based on the phases of the intervention. Furthermore, increased resource availability does not guarantee the sustainment of intervention success. Users need different types of support beyond the technical aspects of an intervention, and this support varies over time. Specifically, available resources in the form of technological support and social/emotional support help users establish trust in a new technological-based intervention during the implementation phase. Resources that foster and maintain collaboration between users and other stakeholders help them stay motivated during sustainment.ConclusionsOur findings highlight the dynamic nature ofavailable resourcesand their impacts on the implementation climate across different phases of implementation. A better understanding of the dynamics ofavailable resourcesover time from the users’ perspectives will allow the adaptation of resources to better meet the needs of the intervention stakeholders.Supplementary InformationThe online version contains supplementary material available at 10.1186/s43058-023-00460-0.