Sustainability transitions have repeatedly been demanded in various economic sectors to confront global environmental problems. The present paper analyses the role of strategic planning processes for improving the prospects of achieving sustainable transitions in infrastructure sectors. Current planning approaches in these sectors tend to perpetuate the established socio-technical configurations by neglecting context uncertainties, by ignoring radical system alternatives and by focusing on narrow value considerations. In order to improve the prospects for sustainable transitions, more reflexive and discursive strategic planning methods are needed. We present the ‘Regional Infrastructure Foresight’ methodology as a specific procedural proposal and analyse results from its application to a case study in the Swiss sanitation sector. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.