The characteristics and the drivers of informal waterfront settlements in Port-Harcourt Metropolis were examined in this study using both quantitative and qualitative approaches. Data were collected on socio-economic, physical and environmental characteristics, perceived risk associated with living in flood-prone areas, the driving forces behind choice of residence in informal settlements and suggested approaches for improving living conditions in the informal settlements in the study area using structured questionnaires which were administered on 386 sampled household heads. Physical observation was equally conducted to identify housing characteristics of the informal settlements in the study area. In-depth interviews were also conducted with the heads of institutional bodies on strategies for addressing informal settlements in the study area. It was revealed through findings that majority of the residents in the informal settlements were male residents, within work force age, fairly educated and married. It was observed that buildings in the settlements were poorly spaced, congested, insufficiently served with basic amenities and were highly vulnerable to flooding, building collapse, sinking and decay. Residents were exposed mainly to risks like water–borne and air-borne diseases, burns from fire outbreaks and property losses due to floods. Thirteen (13) significant divers of informal settlements (factors influencing choice of residency in informal settlements) were analysed and Principal Component Analysis (PCA) extracted four components of eigen values greater than one explaining 67.02% of the total variance. The drivers of informal settlements in the study area was thus summarised into three namely economic, environmental, social and political/institutional. Thus government and other relevant bodies should assist in providing sustainable low-cost, affordable, flood-resistant and hygienic housing and economic empowerment incentives in the study area.