Domestic e-cargo bikes could contribute to the much-needed transition away from individual car use to more sustainable urban mobility. However, while domestic e-cargo bikes are especially popular in some European countries, their adoption remains relatively low in the UK. Adoption can be hindered by negative perceptions and beliefs, but direct experience, such as through trials, can reduce these. This paper aims to understand barriers to e-cargo bike adoption in the UK through the study of perceptions. Our mixed-method approach combines open responses to a nationally representative survey with interview data collected as part of household long-term trial loans in three British cities. With this, we identify and compare barriers as imagined by individuals who have not used an e-cargo bike to the barriers as experienced by people who have used one. We identify three sets of barriers: spatial, material and societal. Our analysis suggests that trials might help address material and societal barriers, while spatial barriers persist among trial participants and require improving cycling infrastructure alongside policies to limit car use. This paper advances scholarship on trial programs as interventions to overcome imagined barriers to sustainable mobility modes, encourage their adoption, and foster sustainable urban mobility transitions more broadly. It also contributes to emerging scholarship on domestic cargo bikes, shifting from logistics focus.