Learning from error is not just an individual endeavour. Organisations also learn from error. Hospitals provide many learning opportunities, which can be formal or informal. Informal learning from error in hospitals has not been researched in much depth so this narrative review focuses on five learning opportunities: morbidity and mortality conferences, incident reporting systems, patient claims and complaints, chart review and prospective risk analysis. For each of them we describe: (1) what can be learnt, categorised according to the seven CanMEDS competencies; (2) how it is possible to learn from them, analysed against a model of informal and incidental learning; and (3) how this learning can be enhanced. All CanMEDS competencies could be enhanced, but there was a particular focus on the roles of medical expert and manager. Informal learning occurred mostly through reflection and action and was often linked to the learning of others. Most important to enhance informal learning from these learning opportunities was the realisation of a climate of collaboration and trust. Possible new directions for future research on informal learning from error in hospitals might focus on ways to measure informal learning and the balance between formal and informal learning. Finally, 12 recommendations about how hospitals could enhance informal learning within their organisation are given.