The use of antenatal colostrum expression in the weeks prior to birth may help improve long-term breastfeeding, but few large-scale studies exist. Typically, antenatal colostrum expression instruction relies on face-to-face education, making large interventions costly. We aimed to determine whether an expert online instructional video can improve knowledge and confidence around antenatal colostrum expressing. Pregnant women were asked to complete a questionnaire pre- and post-watching the instructional video online. Ninety five pregnant women completed both pre- and post-questionnaires. Total antenatal colostrum expression knowledge scores improved after watching the video, from a mean of 3.05 ± 1.70 correct out of a maximum of 7, to 6.32 ± 0.76 (p <0.001). Self-reported confidence around hand expressing in pregnancy also improved from an average ranking of not confident (2.56 ± 1.17, out of a possible 5) to confident (4.32 ± 0.80, p <0.001). Almost all women (98%) reported that they would recommend the video to a friend or family member if antenatal colostrum expression was suggested by their healthcare provider. Findings suggest that the use of an online expert video is an acceptable and effective way to educate pregnant women in antenatal colostrum expression.