This article explores how beliefs affect preferences leading to policy instrument choices of elite actors. Beliefs are general attitudes regarding a given policy field, for example toward the role of the state or the urgency of a problem. Both beliefs and preferences are central for applications of Sabatier's Advocacy Coalition Framework, but their interrelationship has remained undertheorized. Understanding how beliefs and preferences are linked can provide important insights into policy instrument choice, while improving the comparability of studies across policy subsystems. The article compares the relative contribution of beliefs to shaping instrument choices of elite actors in the domain of Swiss renewable energy policy. Results suggest that beliefs are likely to play a prominent role in shaping instrument choice. We find that policy core beliefs translate into preferences through a process involving two main pathways. First, some policy beliefs primarily influence the preferred characteristics of the overall instrument mix. Second, some policy beliefs are primarily associated with preferences for specific instruments. Some policy beliefs are influential via both pathways. These, therefore, emerge as especially important factors shaping the policy process. Our results offer insights for policymakers into how potential future conflicts in negotiations can be attenuated.