Objectives To assess nutrition-related knowledge and practices, including supplement use, of both pregnant women and healthcare providers that participate in antenatal shared care (ANSC). Methods Pregnant women enrolled in ANSC (n = 142) completed a knowledge and practices survey and a validated iodine-specific Food Frequency Questionnaire. General practitioners (GP) and nurses (N = 61) participating in the ANSC program completed a short survey which assessed their knowledge about nutrition for pregnancy, focussing on iodine. Results Both groups had poor knowledge about the importance and roles of iodine during pregnancy. Most women (82%) reported taking a supplement during their current pregnancy, and 70% were taking a supplement containing iodine. Only 26% of GPs discussed iodine supplementation with pregnant patients. The median (IQR) iodine intake of pregnant women was 189 (129-260) μg/day which meets the estimated average requirement (160 μg/day). Half (52%) of women's dietary iodine was provided by dairy foods, and only 7% came from fish and seafood. Most healthcare providers (74%) expressed interest in receiving ongoing professional education about iodine in pregnancy. Conclusion and Implications Ongoing nutrition education for ANSC health practitioners is required to ensure that women receive sufficient dietary advice for optimal pregnancy outcomes. Further research is required to address reasons behind dietary choices of Australian pregnant women.