Objective: The success of COVID-19 vaccination programs relies on community attitudes, yet little is known about parents' views. We aimed to explore the reasons behind Australian parents' vaccine intentions for themselves and for their children. Method: This mixed methods study relates to Wave 13 (January 2021) of a longitudinal study of Australian parents' experiences during COVID-19 and contained 1094 participants (83% mothers). We used multinomial logistic regression to understand demographic predictors of vaccine intention, and a descriptive template thematic analysis to analyse open-ended questions about parents' reasons for vaccine intentions for themselves and their children. Results: 64% of Australian parents intend on vaccination, 26% are unsure and 9% intend to decline; 48% intend to vaccinate their children, 38% are unsure, and 14% intend to decline. Relative to those intending to vaccinate, parents unsure (OR = -0.63, 95% CI: 0.46, −0.84, p = .002) or not intending (OR = -0.41, 95% CI: 0.24, 0.67 p < .001) to vaccinate were more likely to have lower trust in doctors. Similar predictors emerged for parents who did not intend to vaccinate their children (OR = 0.47, 95% CI: 0.31, 0.70, p < .001). Qualitative data indicated that many parents had not made a firm decision, including a lack of alignment between intentions and reasons. For example, parents who said ‘yes’ to vaccination, often then expressed hesitance and a focus on risks in their written response. Reasons for hesitancy for themselves included concerns about testing, side effects, and long-term outcomes. Similar themes were present for children, but parents expressed a strong desire to protect their children, and an eagerness for health information. Conclusion: Based on prior research and the themes identified here, a multipronged campaign that includes education/promotion, good access to vaccines and role models, is likely to support parents to make informed decisions regarding COVID-19 vaccination.