Approximately 2.8 billion people rely on polluting cooking fuels (e.g. wood, kerosene), exposing them to health-damaging household air pollution. A key access barrier to clean cooking fuels (e.g. liquefied petroleum gas (LPG)) is affordability. By enabling households to pay in small increments, pay-as-you-go (PAYG) LPG could help promote clean cooking, and support continued LPG use through periods of economic downturn. We investigate the ability of PAYG LPG to sustain access to clean cooking from January 2018-June 2020, including during COVID-19 lockdown (March-June 2020) in an informal settlement in Nairobi, Kenya. We utilize novel PAYG LPG smart meter data to document cooking/spending patterns from 426 PAYG LPG customers and semi-structured interviews among a subset of seven households. Objective cooking pattern comparisons are made to those cooking with full 6kg cylinder LPG and polluting fuel users from 23 households in peri-urban Eldoret in western Kenya, using stove monitoring data. Customers’ average PAYG LPG consumption was 0.97 kg/capita/month (11.6 kg/capita/year) prior to COVID-19 lockdown. Despite adverse economic impacts of the lockdown, 95% of households continued using PAYG LPG, and consumption increased to 1.22 kg/capita/month (March-June 2020). Daily cooking events using PAYG LPG increased by 60% (1.07 events/day (pre-lockdown) to 1.72 events/day (lockdown)). In contrast, among seven households purchasing full 6kg cylinder LPG in Eldoret, average days/month using LPG declined by 75% (17 to four days) during COVID-19 lockdown. Median PAYG LPG payment frequency doubled (from every 8 days to every 4 days) during lockdown, while average payment amount was nearly halved (336 Kenyan Shillings (KSh)/US$3.08 to 179 KSh/US$1.64).Interviewed customers reported numerous benefits of PAYG LPG beyond fuel affordability, including safety, time savings, cylinder delivery and user-friendliness. PAYG LPG helped sustain clean cooking during COVID-19 lockdown, possibly averting increases in polluting cooking fuel use and associated household air pollution exposures.Graphical AbstractHighlightsFirst study to report long-term cooking/spending patterns using PAYG LPG smart meter data95% of 301 active PAYG LPG customers in February 2020 continued to use the fuel during COVID-19 lockdownDaily cooking events using PAYG LPG increased by 60% during COVID-19 lockdownMedian payment frequency increased 50%, while single payment amount decreased 50% during lockdownThree-quarters of PAYG LPG households in this study were first time LPG users