Background Teenage marriage and adolescent pregnancy present a significant health challenge in the Tanzania. About 36% of women aged 15-49 are married before the age of 18, and 32% of rural adolescents (10-19 years) gave birth, compared with 19% of urban. In Mwanza region, one third of currently married adolescent and women aged 15-49 experienced unmet need for family planning and had low use of modern contraceptives. Here we present a study that explored the gaps in accessing and utilization of quality adolescent sexual and reproductive health services (ASRH). Methods This was a descriptive and exploratory cross-sectional formative study utilizing multiple qualitative research methods. Purposive sampling was used to select an urban district (Nyamagana), rural district (Magu) and an island (Ukerewe). Sixty-seven IDI and 30 focus group discussions (FGDs) stratified by gender (12 out-of-school, 12 in-school), and (3 male, 3 female adults) were purposefully sampled. Vignettes were done with 15-19 years old in-school and out-of-schools boys and girls. An experienced moderator, along with a note-taker, led the discussions while taking notes. The FGDs were recorded using an MP3 voice recorder. Thematic analysis approach was undertaken and data was analysed using NVivo 12, a qualitative software. Results The identified the most important pressing needs of the adolescents in relation to SRH. Adolescent girls needed specific services such as counselling on menstrual health, sexual consent, HIV/AIDS, and prevention of pregnancies. Sanitary pads during menstrual period were very important pressing need of the adolescent girls. Adolescents both girls and boys preferred to receiving friendly health care services in a respectful manner. Girls mentioned that they would like to receive SRH support from nurses in health facilities, mothers, sisters, aunties and friends. With regards to boys, they preferred to receive the SRH from health care providers followed with their peer’s friends. Several obstacles were reported to hinder access to SRHS predominantly among the adolescent girls as compared to the boys. Poor infrastructure tended to impair the privacy at the health facilities, and rarely there were specific buildings to provide friendly adolescent sexual and reproductive health services. Conclusions The strategies to guide delivery of ASRH should involve the inclusion of duty bearers, promotion of friendly health care services where health workers provide services in friendly-manner, provision of ASRH education for awareness creation to adolescents and supportive parents/ care takers.