Division-control is a fundamental aspect of the life cycle of organisms reproducing through fission. While regulation of division rates have been studied in bacteria and yeast, much less is known about division control in multicellular organisms due to a lack of data. We have, over the course of several years, assembled a unique large-scale data set on the growth and asexual reproduction of two freshwater planarian species, Dugesia japonica and Girardia tigrina, which reproduce by transverse fission and succeeding regeneration of head and tail pieces into new planarians. Analyzing the data with a biophysical model, we discovered diverse division control strategies not only across different species, but across different types of offsprings of the same species. We have also revealed generational memory in the division dynamics. Our findings can serve as a point of departure for future studies on the molecular mechanisms governing planarian asexual reproduction.