Age-appropriate paediatric formulations are needed to achieve optimal medication adherence in children. In Europe and the United States, the acceptability of mini-tablets was compared to that of liquid formulations, which are commonly used as paediatric formulations. In Japan, fine granules are also commonly administered to children. This study was performed to examine the acceptability of mini-tablets, fine granules, and liquid formulations by children. This prospective, single-centre, three-period crossover, randomised controlled trial included children aged 2-8 years who were visiting a paediatric department in Showa University Hospital and had experience in taking medicine. The primary endpoint was the measure of acceptability by observation of healthcare professionals according to pre-defined evaluation criteria. Sixty-five subjects including low-aged (2-<4 years, n = 12), mid-aged (4-<7 years, n = 29), and high-aged (7-<9 years, n = 24) children were enrolled. Most subjects accepted all formulations, although mini-tablets showed lower swallowability compared to fine granules and liquid formulations. Fine granules and liquid formulations showed good acceptability and swallowability, and mini-tablets were accepted by Japanese children, although the swallowability was lower, likely because children tend to chew on mini-tablets.