Abstract The impact of the insular nature of prison environments is usually studied from the perspective of incarcerated persons. This article presents key findings from an ethnographic study in a Belgian telephone pole‐style prison, exploring the experiences of prison officers working in single‐staffed units and the impact on the occupational culture. Drawing on the emic term ‘islands’ used by prison officers in this study to metaphorically depict both the material and psychological work environment, this article discusses the impact of specific work conditions within this prison setting, such as the detrimental effect of prison officer isolation on staff cohesion, solidarity and functional staff–prisoner relationships. Moreover, the results show that certain factors, such as local prison policy, digital communication and prison layout, may contribute to or reinforce insularity.