PurposeClimate impacts are a significant challenge in slums and informal settlements, most of which are located along the coast. This article aims to show coping strategies and flood adaptation opportunities through the case study of a coastal slum in Lagos, Nigeria.Design/methodology/approachA mixed-method approach is used in Idi-Araba settlement, Oworonshoki, Lagos – the case study area. Data collection involved semi-structured interviews with 15 purposively selected residents and a survey (sample size = 300 residents). A town hall meeting was convened to disseminate the findings and gather feedback from the community.FindingsBeing an informally developed settlement, flooding affects the poor-quality buildings – a situation made worse by absence of infrastructure and services. Coping with flooding involves structural strategies (raising building’s foundation, re-roofing, sand-filling the surrounding, etc.), failed attempt through green infrastructure, nonstructural measures through dietary pattern, dressing, etc. These measures emanate from self-help and community efforts, attesting to notable social capital in the study area. They are minimally effective and limited, which highlights adaptation gaps and opportunities.Research limitations/implicationsThis study calls for transformative adaptation, beyond the current coping and maladaptation. It argues that local strategies need to meet with innovative substantive external initiatives from the state and third sector.Originality/valueThis study considers the single case of a coastal settlement in Lagos. This focus allowed detailed examination within a representative settlement, much unlike city-wide, cross-settlement considerations in many other studies. It provides additional empirical evidence on limitations of self-help flood coping measures and adaptation prospects in the often overlooked low-income, informal urban sector.