Switzerland and Europe are currently at a crossroads with respect to its electricity policy. Several existing nuclear and fossil fuel power plants are to be retired in the coming years. Meanwhile, ambitious carbon dioxide (CO₂) emission reductions are envisaged, which could penalise fossil power plants and encourage investments in renewable-based electricity generation. Switzerland and a few other countries in Europe have decided to phase-out their nuclear capacity, thereby removing a low-carbon source of electricity in the medium- to long-term future. In order to understand possible electricity transition pathways for Switzerland, electricity supply options for Switzerland and its four neighbouring countries namely Austria, France, Germany and Italy are analysed to assess non-nuclear alternatives under a stringent climate mitigation policy. The cross border Swiss TIMES electricity model (CROSSTEM), a cost optimisation framework with a long time horizon and an hourly temporal resolution, is used for this analysis. In the absence of any CO₂ emission reduction targets, gas-based generation supplemented by electricity imports is the cost-effective alternative to nuclear for Switzerland. For a low carbon electricity system, natural gas based generation with Carbon Capture and Storage (CCS), complemented by an accelerated investment in renewable generation is required. Traditional electricity trade patterns have to be revised, with significant increases in cross-border interconnector capacities necessary to transfer electricity to Switzerland from countries with abundant renewable resources such as Germany and Italy. The average cost of electricity in a decarbonised electricity sector would increase in the range of 30-120% by 2050 compared to today, depending on the scenario assumptions. The availability of CCS technology and the requirement for electricity storage are particularly important to achieve a complete decarbonisation of the electricity sector with a nuclear phase-out.