Retail merchants play a central role in driving the shift towards cashless payments. They operate within an interconnected cashless payment ecosystem, interacting directly with other actors through collaboration and competition. This study examines retail merchants’ interactions with other participants in the ecosystem, focusing on the concept of coopetition—a combination of cooperation and competition. We conducted a qualitative reflexive thematic analysis of 15 semi-structured interviews with retail merchants in Sweden. The analysis yielded five themes: Harmonizing for optimal integration, strategizing cost efficiency, balancing reliability and risk management, aligning with consumer preferences and market dynamics, and managing the evolution of payment technologies. The study contributes to the existing literature by offering a rich contextual description of retail merchants’ interaction within the cashless payment ecosystem. It highlights the importance of coopetitive interactions for retail merchants to enhance their payment operations, stay competitive, and respond to market and technological changes. These insights can guide retail merchants and other actors in optimizing their strategies for successfully implementing cashless payment systems.