The Sendai Framework for Disaster Risk Reduction 2015-2030 recommends several actions for early warning systems (EWSs). However, there is a lack of information about their means of implementation. This article used institutional ethnography to analyze the 2012-2018 implementation of a national warning system in Brazil. The challenges related to daily activities, and the interdisciplinary works in the four axes of EWSs towards multi-hazard and people-centered approaches are discussed. This national experience is then discussed in the light of the global challenges of EWSs considering two main issues: (1) experiences of implementation and barriers related to people-centered warning systems; and (2) types of national/regional warning systems and hazards/ threats that are being monitored as an important input for multi-hazard approaches. There are few multi-hazard warning systems in place and EWSs are focused on hydrometeorological hazards, mainly related to floods. The Sendai Framework needs to improve access to data and information, identify views from the frontline, consider political threats and vulnerabilities, and find ways to talk about disaster risk creation processes at a larger scale.