Background: Trans and gender diverse individuals (people who identify with a gender different to what was presumed for them at birth) are one of the most medically and socially marginalized groups in our community. The COVID-19 pandemic may compound preexisting depression and thoughts of self-harm or suicide. Aim: We aimed to explore the impact of the COVID-19 pandemic on the Australian trans community. Methods: An online cross-sectional survey was conducted between 1st May 2020 and 30th June 2020, amidst strict Australia-wide social restrictions. Australian trans people aged ≥16 years were eligible to participate. Survey questions explored the impact of the COVID-19 pandemic on living situation, employment, financial situation, and healthcare. Logistic regression to assess negative impacts due to COVID-19 on depression and thoughts of self-harm or suicide (measured by Patient Health Questionnaire-9 (PHQ-9) are presented as odds ratios (95% confidence interval)). Results: Of 1019 participants, 49.6% reported experiencing financial strain, 22% had reduced working hours, and 22.4% were unemployed (three times the national rate). Concerningly, 61.1% experienced clinically significant symptoms of depression (Patient Health Questionnaire-9 score ≥10), considerably higher than pre-COVID rates for the trans community and over twice the national rate. Moreover, 49% reported thoughts of self-harm or suicide (over three times the national rate) which was more likely if a person experienced cancelation or postponement of gender-affirming surgery (OR 1.56 (1.04, 2.35)), financial strain (OR 1.80 (1.36, 2.38)), or felt unsafe or afraid in their household (OR 1.96 (1.23, 3.08)). Discussion: Given rates of clinically significant depression and thoughts of self-harm or suicide are far higher in trans people than the general population, specific strategies to improve mental health in the trans community during the COVID-19 pandemic must be made a priority for policymakers, researchers, and health service providers to prevent suicide.