This study examines how autonomy and improvisation jointly shape the emergence of springboard opportunities and the stability of customer relationships in internationalizing small and mid-sized firms. While rapid international expansion requires agility, firms must simultaneously maintain trust and continuity with foreign partners. Drawing on international entrepreneurship, effectuation, and springboard perspectives, we conceptualize autonomy as a structural and cultural condition that enables managers to act decisively under uncertainty. We argue that autonomy facilitates improvisational decision-making, which in turn enhances firms’ ability to exploit capability-enhancing springboard opportunities. Improvisation also contributes directly to relational stability by enabling responsive adaptation to customer needs. Using data from 168 firms and 258 foreign market entries, we propose and test a structural model linking autonomy, improvisation, springboard opportunities, and relationship stability. The findings advance understanding of how adaptive decision processes support accelerated internationalization while preserving long-term relational continuity in global business networks.