Background The endgame literature recommends that, for a tobacco sales ban to be successful, several demand-side preconditions (eg, low prevalence and effective cessation support) should be in place. The South African Government imposed a ban on the sale of all tobacco and vaping products between 27 March and 17 August 2020, as part of the COVID-19 lockdown.Objectives To assess how cigarette smokers responded to the sales ban, to evaluate how the ban impacted the cigarette market in South Africa and to use the South African experience to inform endgame planning.Methods Regular preban cigarette smokers completed an online questionnaire from 4 to 19 June 2020 (n=23 631), in which they reported on their prelockdown cigarette smoking patterns, quitting behaviour (if relevant) and smoking behaviour during the ban.Results About 9\% of prelockdown smokers in the sample successfully quit smoking. 93\% of continuing smokers purchased cigarettes despite the sales ban. The average price of cigarettes increased by 250\% relative to prelockdown prices. Most respondents purchased cigarettes through informal channels.Conclusions The demand-side preconditions for an effective sales ban were not in place in South Africa, making a sales ban inappropriate. The South African experience suggests that supply-side factors are also important in ensuring the success of a sales ban. These are: (1) the illicit market must be under control before implementing a sales ban; and (2) an effective sales ban needs to be synchronised with a ban on the manufacture, transport and distribution of cigarettes.Data are available in a public, open access repository. Data are available on the DataFirst Open data portal: https://www.datafirst.uct.ac.za/dataportal/index.php/catalog.