Climate change has made urban decarbonisation a global imperative. Cities are both a source of emissions and a leverage-point for the necessary transformation processes. Iceland is blessed with an ample supply of renewable energy sources. Hydropower and geothermal are widespread in the country and they dominate the country's electricity and district heating systems. Despite this huge potential, per capita emissions in Iceland are still way above levels required to meet the 2 degrees target. This is because decarbonisation processes have, so far, fallen short of addressing emissions from sectors such as waste and transportation. Against this background, this paper investigates the low carbon transition in the northern Icelandic municipality of Akureyri. With roughly 18,000 inhabitants, the town of Akureyri is the biggest urban centre in the north of the country. Here, a number of key actors have initiated an ambitious urban transformation process of local carbon flows. Based on 19 semi-structured interviews, we analysed the role of key actors and their resources and strategies. To better explore the transition's underlying mechanisms, we analysed the dynamics through the lens of the multi-level perspective (MLP), applied in a descriptive context. We found that a key factor for success of the urban transition was a strategy that integrated several previously disconnected carbon flows of the community. Important success factors were close community connections, public-private partnerships, the enthusiasm of multiple individuals who drove the process, the establishment of a strong intermediary organisation, and stable political support. The case can teach us about the challenges of transitions that integrate disconnected carbon flows in an urban context. Furthermore, it provides valuable findings on the role intermediary organisations play in these processes.