S Pav is a bright southern semiregular with a primary pulsation period near 400 days. Over extended periods of time, the light curve shows clear evidence of variations in the light curve that may be due to secondary pulsation modes. When multiple periods are present in a light curve, they often beat together in time, producing long-term changes in amplitude and light curve shape.
S Pav has historically ranged from mid-6th magnitude to mid-10th, but it more typically remains around m(vis)=8, ranging from 7th to 9th. Although its period puts it among the Mira variables, the strongly varying light curve and smaller amplitude puts it firmly in the semiregular category.