Sua Pan is the eastern of the two twin pans, and extends roughly southwards from the town of Nata in its northeast corner. On its southern shore is the village of Mosu; to its north lies the Maun-Nata road; to its west it is divided from Ntwetwe Pan by a thin strip of grassland. Sua (sometimes spelt 'Sowa') is the Tswana word for salt, and this mineral residue from the vanished super-lake dominates the geology and ecology of the pan.
Once salt was laboriously collected from the pan surface by the San and carried away on donkeys. Today it is mined by the Sua Pan Soda Ash Company – a joint South African and Botswana government enterprise – who supply sodium carbonate on an industrial scale for use in the manufacture of paper, glass and steel. Their mine is situated along the Sua Spit; a tongue of grassland that extends halfway across the pan from its eastern shore.
The Nata River feeds Sua Pan from the northeast (bringing the rains from Zimbabwe) and, in good years, it floods from December to April with shallow, warm water. Where the fresh water of the river meets the saline pan, a brackish delta of silted reedbeds has formed. In summer, this corner of the pan attracts great concentrations of breeding waterbirds, notably flamingos (see Fauna below). This delta is now protected within the Nata Sanctuary – an area of 230km2. The flamingos can usually be viewed from the bird hide on the eastern shore.
Evidence of the former lake exists in the form of fossil pebble beaches along the shores of Kubu Island and other granite outcrops around the pan, and fossil diatoms and molluscs on the pan surfaces. These reveal that there was a prolonged wet period about 14,000–17,000 years ago and, more recently, a flood only 1,500 years ago. Near the village of Mosu in the south, an escarpment rises some 40 metres above the edge of the pan, showing the erosive force of the great lake that once washed against these cliffs. Here there is also one of several subterranean springs that emerge around the fringes of the pans.