Purpose: This paper aims to investigate student experiences and the potential impact of experience-based learning (EBL) in the early phase of graduate sustainability programs through the lens of key competencies. The goal is to provide evidence for the improvement of existing and the thorough design of new EBL formats in sustainability programs. Design/methodology/approach: This comparative case study focuses on the first semester of three graduate sustainability programs at Leuphana University of Lüneburg, Germany and Arizona State University, USA, for two of which EBL was a core feature. The study compares the curricula, the teaching and learning environments and the reported experiences of one student cohort from each of three programs and synthesizes the resulting insights. Student interviews were combined with student self-assessments and supported by in-vivo observations, curriculum designer input, instructor interviews and course materials. MAXQDA was used for data analysis following a grounded theory approach. Findings: EBL influences students’ reflective capacity, which impacts the development of key competencies in sustainability. Qualitative analysis found four key themes in relation to the students’ learning in EBL settings, namely, discomfort, time-attention relationship, student expectations of instructors and exchange. The intersection of these themes with curricular structure, student dispositions and differing instructor approaches shows how curriculum can either support or interrupt the reflective cycle and thus, holistic learning. Research limitations/implications: With the focus on the first semester only, the students’ competence development over the course of the entire program cannot be demonstrated. Learning processes within EBL settings are complex and include aspects outside the control of instructors and curriculum designers. This study addresses only a select number of factors influencing students’ learning in EBL settings. Practical implications: Early engagement with EBL activities can push students to leave their comfort zones and question previous assumptions. Designing curricula to include EBL while encouraging strong intra-cohort connections and creating space for reflection seems to be an effective approach to enable the development of key competencies in sustainability. Originality/value: This paper investigates the experiences of students in EBL through a key competence lens. The study combines student self-perceptions, instructor reflections and in-vivo observations. Data collection and analysis were conducted by a researcher not affiliated with the programs. These factors make for a unique study design and with data-driven insights on the seldom researched competence-pedagogy-curriculum connection.