INTRODUCTION: Connecting2u (C2u) is a mobile health (mHealth) intervention supporting Queensland families. The 2021-2023 iteration focused on the first 2 years of a child's life. This study evaluated whether C2u supported maternal and child well-being during this period. METHODS: This longitudinal study used a self-administered online survey at four points over 2 years. Survey items included the Karitane Parenting Confidence Scale, Modified Medical Outcome Social Support survey, child immunisation status, agreement statements, and open-ended questions on C2u support and satisfaction. Parenting confidence and social support were modelled using linear quantile mixed models; univariate and qualitative content analysis were applied to remaining items. RESULTS: Parenting confidence increased over the first 12 months, with faster improvements among first-time parents and modestly faster gains among parents with university-level education. Social support scores showed little change over the 2-year period, although qualitative data suggested C2u encouraged conversations between parents. Agreement statements indicated that C2u was well received and supported preventative health behaviours. Qualitative feedback reinforced these findings, with participants describing C2u as an extra layer of support, prompting self-care, encouraging bonding with their child, and offering timely guidance on introducing solids. By the end of the study, 100% of participants indicated their child had received the full schedule of age-appropriate immunisations. CONCLUSIONS: C2u was well received by mothers. Enhancing its focus on partner support, expanding social support networks, guidance on sibling bonding, and self-care strategies could be beneficial. Queensland Health could consider implementing an online booking system to streamline child health appointments. So what? C2u is an innovative mHealth intervention. Our findings support refinement as C2u expands to include antenatal care messaging and support for children up to 5 years, helping to optimise outcomes for families.