The interconnectedness of Central Asia and the South Caucasus region is facilitating new regional cooperation opportunities beyond traditional multilateral institutions. This article examines the emerging trilateral format among Azerbaijan, Turkmenistan and Uzbekistan as a practical mechanism for advancing cooperation in transport, energy and trade across the Greater Caspian region. It asserts that the format represents a type of functional minilateralism, emphasizing the implementation of concrete projects rather than the expression of broad political statements. Particular attention is given to recent developments following the 2025 Turkmenbashy summit and the state visit of Turkmenistan’s President Serdar Berdimuhamedov to Azerbaijan in June 2026, which have strengthened cooperation in logistics, customs, industrial policy and energy. The article further assesses the trilateral mechanism within the broader process of institutionalizing the C6 framework, suggesting that smaller, project-oriented formats can serve as effective platforms for testing practical solutions before their wider regional application. It concludes that the Azerbaijan–Turkmenistan–Uzbekistan partnership has the potential to become an important implementation track linking Central Asia, the South Caucasus and Europe through enhanced trans-Caspian connectivity and sectoral cooperation.