To estimate the effect of income change on difficulty accessing food since the COVID-19 pandemic for South African youth, and evaluate whether this effect was modified by receiving social grants. A cross-sectional, online survey was conducted between December 2021 and May 2022. Primary outcome was increased difficulty accessing food since the COVID-19 pandemic. Income change was categorized as "Decreased a lot", "Decreased slightly" and "Unchanged or increased". Multivariable logistic regressions were used, with an interaction term between social grant receipt and income change. eThekwini district, South Africa. Youth aged 16-24 years. Among 1,620 participants, median age was 22 years (IQR 19-24); 861 (53%) were women; 476 (29%) reported increased difficulty accessing food; 297 (18%) reported that income decreased a lot, of whom 149 (50%) did not receive social grants. Experiencing a large income decrease was highly associated with increased difficulty accessing food during the COVID-19 pandemic (adjusted odds ratio [aOR] 3.63, 95% Confidence Interval [CI] 2.70-4.88). The aORs for the effect of a large income decrease on difficulty accessing food, compared to no income change, were 1.49 (95%CI 0.98-2.28) among participants receiving social grants, and 6.63 (95%CI 4.39-9.99) among participants not receiving social grants. While social grant support made a great difference in lowering the effect of income decrease on difficulty accessing food, it was insufficient to fully protect youth from those difficulties. In post-pandemic recovery efforts, there is a critical need to support youth through economic empowerment programming and food schemes.