Satellite remote sensing has long been used for tracking, modeling and estimation of reservoir state in regulated rivers before the advent of the Surface Water and Ocean Topography (SWOT) mission. Most such methods using single or multiple sensors relied on ad hoc approaches to estimate storage change as simultaneous measurement of areal extent and elevation was not available from any sensor. Now that we are in the SWOT era with unprecedent capability to simultaneously track both water extent and elevation, our study asks the question “How well can we track global reservoir relative to the pre-SWOT era or non-SWOT sensors?” We carried out this study over 245 reservoirs around the world with highly accurate storage data overlapping SWOT observations from mid-2023 to end of 2024. We used a multi-sensor (non-SWOT) reservoir storage algorithm called TMS-OS based on optical (Landsat, Sentinel-2) and microwave (Sentinel1) sensors as the non-SWOT baseline for comparison. Our study revealed that SWOT can yield an order of magnitude better estimation of absolute storage with the use of in-situ reservoir bathymetry information. SWOT’s performance holds up across climate, elevation, shape and capacity, demonstrating a consistent reliability for global use. Trends in reservoir storage change are also better and more consistently captured than what is possible with non-SWOT sensors. Building on this very promising finding, our future study goal is to apply SWOT data to create accurate reanalysis of global reservoir storage data from the 1980s, improve capacity loss monitoring due to sedimentation of reservoirs and understand how harmful algal blooms (HAB) behave in regulated river systems by building synergy between SWOT and the recently launched PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite mission. With a large water practicing community now eager to benefit from SWOT, our future study will usher the community to improved water management practices where reservoir operations can be optimized for long-term sustainability and ecosystem function goals with SWOT data.