The promotion of commercial milk formula (CMF) negatively impacts breastfeeding outcomes. In 2019, Singapore updated its 1979 Code of Ethics of the Sale of Infant Foods Ethics Committee Singapore (SIFECS) to increase marketing restrictions on CMF for infants 0–12 months. However, little is known about industry tactics to undermine these restrictions. This qualitative study explores health workers' and mothers' experiences with CMF marketing in Singapore following the 2019 restrictions. We conducted a qualitative study, using semistructured interviews with 14 mothers of infants aged less than 5 months and 20 health workers with expertise in antenatal, maternity, or paediatric care. We analysed data thematically using inductive coding. Five themes were identified. Mothers and health workers reported digital marketing, product line extensions with toddlers' milk and milk for mothers, and CMF sponsorships in the healthcare setting. Expert endorsement, competitive price, nutritional claims, and brand reputation influenced mothers' infant formula choices, yet both mothers and health workers appeared to be unaware of the impact of CMF marketing tactics on their own perceptions. The restriction of CMF marketing and infant feeding practices varied widely between hospitals, with private hospitals and practices having less strict controls on CMF marketing. Despite the updated SIFECS restrictions, CMF companies continue to target mothers and health workers in Singapore. SIFECS restrictions should be tightened to align with international guidelines, by increasing their scope to include toddlers' milk and prohibiting cross‐promotion, digital marketing, and any sponsorships of events targeting health workers that may create a conflict of interest.