Science diplomacy is becoming an important tool by which states can more effectively promote and secure their foreign policy agendas. Recognising the role science plays at national and international levels and identifying a state’s national diplomatic style can help to construct a ‘national style’ in science diplomacy. In turn, understanding science diplomacy can help one evaluate a state’s potential for global governance and to address global issues on a systematic scale. By using a Realist framework and by testing proposed hypotheses, this study highlights how different national styles in science diplomacy affect competition between major powers and their shared responsibility for global problems. This study adds to our general understanding of the practice of diplomacy as it intersects with the sciences.