As birthrates decline and the population ages globally, the healthy age of older adults is increasing, and the need for sustainable participation in society is growing. Older adults can experience subjective well-being, namely, a sense of Ikigai (motivation to live), when they readily engage in meaningful activities. However, to support this, there is a need for a system that recommends such activities, and a method to measure the subjective experience of Ikigai in specific activities is yet to be developed. This study investigates the estimation of social engagement in enhancing the Ikigai of older adults based on communication during the volunteer activity. Focusing on voice communication during frailty checkup activities, we aim to develop a method to measure the subjective perception of Ikigai using objective indicators. We analyzed speech data from 16 older volunteers using advanced audio processing techniques and sentiment analysis. Based on our findings, it seems that individual speech features and group interactions can provide some indication of an individual’s Ikigai.