Informal settlements have become integral to the urban imagery of the cities across the global South. Forms of urban informality emerge and grow through some generative processes of self-organisation and incremental adaptations. While formal interventions have often failed to put an end to such a resilient and complex type of urbanism, the desire for eradication and demolishment still prevails. Most of the informal settlements can benefit from incremental upgrading and micro-scale design interventions, which then rely on a sophisticated understanding and analysis of informal morphologies and adaptations. However, forms of urban informality and adaptations of informal settlements are relatively understudied. This paper aims to explore informal morphologies and their incremental adaptations drawing on empirical evidence from the case study of Khlong Toei district in Bangkok (Thailand). Direct observation, visual recording, and urban mapping are the key research methods. Five different forms of informality and adaptations have been identified in this study. One of the findings of this study is that informal morphologies emerge in different forms at multiple scales. Another finding of this study is that informal adaptations are often similar across different informal morphologies. The findings of this paper contribute to the growing body of knowledge in urban morphology and informal urbanism.