Despite bisexual people being found to have significantly poorer mental health than their gay, lesbian and heterosexual counterparts, research into their experiences of mental health service use remains sparse. This paper presents findings from one of the largest studies of bisexual people to date (n = 2651) and examines their access to, and experiences with, mental health services. The Who I Am study surveyed adults living in Australia who reported bisexual identity, attraction and/or experience. Univariate analyses and chi square tests were conducted to quantify experiences of mental health service use and how this use is associated with gender and psychological distress. Results of an ordinal logistic regression analysis identify psychosocial predictors of disclosure/non-disclosure of bisexuality in the healthcare setting. Findings suggest that while bisexual people are highly engaged in mental health services, there are barriers to disclosure of their sexual orientation. In addition, the majority of respondents reported wanting more access to services specialising in working with bisexual people. Gender and psychological distress were found to be significantly associated with most service use variables. Despite high levels of engagement in mental health services, barriers to care still exist for bisexual people. Findings presented in this paper provide new insights into the experiences of bisexual people accessing mental health services. These findings will inform future policy development which will direct improved services delivery in this field.