This study investigates durational differences in syllable-final nasals in Japanese, English, and Korean, and examines the mora hypothesis in Japanese. The phenomenon that syllable-final nasals are longer when followed by a voiced consonant than when followed by a voiceless consonant was observed in languages of different timing categories, i. e. Japanese (moratimed), Korean (syllable-timed), and English (stress-timed). However, syllable-final nasals in Japanese (the mora nasal /n/) are set apart with respect to the moraic status: syllable-final nasals (moraic) are clearly differentiated in duration from syllable-initial nasals (non-moraic).