Atoll reef islands are highly vulnerable to extreme water levels due to their low elevation. The dynamics of barrier reef-lagoon systems is known to be strongly controlled by tides and incident swell, which modify the momentum balance across the reef through wave breaking over the reef top. In the case of extensive lagoon systems, local winds blowing in the direction of maximum fetch are also able to generate wind setup and wind seas, which also contribute to the inner lagoon circulation. To date, the spatial variability of sea states and water levels across extensive atoll-lagoon systems has been little investigated due to lack of data in these isolated regions. Wide-swath altimetry from radar interferometry is now opening new doors for coastal altimetry, with improved resolution and 2D spatial mapping. In this study, we investigate the capacity of the recently launched radar interferometer instrument onboard the SWOT satellite mission to monitor water levels, significant wave height (Hs) and wind variability across Rangiroa atoll. The Level 2 SWOT products provide new insights on Hs variability in both offshore waters and within the lagoon, in synergy with water levels and wind measurements.