The global trend in HIV incidence overall is declining; however, there is a plateau in new HIV infection among men who have sex with men (MSM) and transgender women (TGW) despite extensive investment in HIV prevention targeting these populations. Many studies usually conflate these two groups together, which may overlook many disparate characteristics unique to each population, impeding the efficacy of HIV interventions. To better understand the vulnerable diversity that may put these individuals at risk of HIV infection, we conducted qualitative analysis among Thai MSM and TGW, aiming to identify sexual pattern themes of MSM and TGW in Bangkok in order to better understand their distinctive sexual life context. Convenient and purposive samplings were used to recruit Thai MSM and TGW aged ≥ 18 years old and living in Bangkok, Thailand, for focused group discussions and one-on-one in-depth interviews, respectively. Total of 12 MSM and 13 TGW participated in focused group discussions, which were conducted separately for MSM and TGW. Additionally, 5 MSM and 5 TGW were involved in one-on-one in-depth interviews. Thematic analyses were performed separately for MSM and TGW. The results show that MSM and TGW have distinct and diverse sexual patterns, and within the identified themes: partnering, partner finding, protection, and enhancing sexual pleasure (only for MSM). Participants reported having varying sexual experiences. Recognizing the difference and diversity in partnering and sexual practice of MSM and TGW is crucial in order to develop tailored interventions that suit the vulnerability of the key populations in Thailand.