This record contains data on birth and division times, as well as on birth and division lengths, of single cells of the cyanobacterium S. elongatus. Data for wild type and clock-null (deletion of kaiBC operon) cells are included. 3 environmental conditions (constant light, graded 12 h light : 12 h dark, and graded 16 h light : 8 h dark) were assayed. Data were obtained from time-lapse microscopy movies, which were acquired on an inverted Nikon Ti-E microscope. Acquired images were subsequently analysed in Matlab using the software Schnitzcells.