Background: Opportunities for women and providers to use decision aids and share decisions about birth after caesarean in practice are currently limited in Japan. This is despite known benefits of decision aids to support value-sensitive healthcare decisions. Aim: To explore Japanese women's decision making experiences using a decision aid program for birth choices after caesarean. Methods: A mixed methods study was conducted among 33 consenting pregnant women with previous caesarean in five obstetrics institutions located in the western part of Japan. Outcome measures included change in level of decisional conflict, change in knowledge, and preference for birth method. Semi-structured interviews examined women's decision making experiences, and qualitative data were analyzed using thematic analysis. Findings: The participants in the program experienced a statistically significant improvement in knowledge and reduction in decisional conflict about birth after caesarean. Four themes were identified in the qualitative data related to decision making: change in women's knowledge about birth choices, clarifying women's birth preference, feelings about shared decision making, and contrasting feelings after receiving information. Discussion: This study confirmed potential benefits of using the decision aid program. However, uncertainty about mode of birth continued for some women immediately prior to the birth. This finding emphasized the need to identify additional ways to support women emotionally throughout the process of decision making about birth after caesarean. Conclusions: It was feasible to adapt the decision aid for use in clinical practice. Future research is necessary to examine its effectiveness when implemented in Japanese clinical settings.