Introduction Despite prioritization, routine antenatal influenza vaccine coverage is <16% in South Africa. We aimed to describe maternal influenza vaccine coverage in 27 antenatal clinics (ANCs) in Gauteng and Western Cape (WC) Provinces, where in collaboration with the Department of Health (DoH), we augmented the annual influenza vaccination programme among pregnant women. Methods From 2015 through 2018, 40 230 additional doses of influenza vaccine were added to the available stock and administered as part of routine antenatal care. Educational talks were given daily and data were collected on women attending ANCs. We compared characteristics of vaccinated and unvaccinated women using multivariable logistic regression. Results We screened 62 979 pregnant women during the period when Southern Hemisphere influenza vaccines were available (27 068 in Gauteng and 35 911 in WC). Vaccine coverage at the targeted clinics was 78.7% (49 355/62 682), although pregnant women in WC were more likely to be vaccinated compared to those in the Gauteng (Odds ratio (OR) =3.7 p<0.001). Women aged 25—29 and >35 years were less likely to be vaccinated than women aged 18—24 years (OR=0.9 p=0.053; OR=0.9 p<0.001). HIV positive status was not associated with vaccination (OR=1.0 p=0.266). Reasons for not vaccinating included: vaccine stock-outs where ANCs depleted available stock of vaccines and/or were awaiting delivery of vaccines (54.6%, 6949/12 723), refusal/indecision (25.8%, 3 285), and current illness that contraindicated vaccination (19.6%, 2 489). Conclusion Antenatal vaccination uptake was likely improved by the increased vaccine supply and vaccine education offered during our campaign.