This study aimed to explore all the relevant subtypes of cognitive frailty among Japanese community-dwelling older adults with multimorbidity. Moreover, it examined the associations between these potential subtypes of cognitive frailty and social relationships. This study targeted relevant cross-sectional data regarding community-based older adults with multimorbidity. It employed a person-centered method to perform a latent class analysis and explore the subtypes of cognitive frailty among older adults. Moreover, a multinominal logistic regression analysis was employed to examine the association between potential subtypes of cognitive frailty and social relationships. Data for 396 participants (mean age, 75.8 [SD, 7.3] years; 51.3% females) were analyzed. Three cognitive frailty subtypes were subsequently revealed: the robust group (42.0%), the group with partial cognitive frailty (38.6%), and the group with cognitive frailty (19.4%). People with high levels of social relationships were more likely to be in the robust and the partial cognitive frailty groups. This study identified different subtypes of cognitive frailty among multimorbid older adults and highlighted the significance of social relationships. These findings could serve as a reference for conceptualizing cognitive frailty through the person-centered method. Promoting a high level of social relationships could be useful to prevent the cognitive frailty among older adults with multimorbidity.