Since 2016, China has been conducting military flybys around Taiwan, while the US has approved arms sales to Taiwan on several occasions and sent warplanes and battleships through the Taiwan Strait. How does Taiwanese public opinion respond to the Chinese and US military presence in the Strait? Is the public likely to become less supportive of de jure independence for Taiwan on account of China's military deterrence or more supportive owing to a perceived likelihood of US military assistance? In this report, we provide answers to these questions based on evidence from a survey experiment conducted in Taiwan in October–November 2020. We find that Taiwanese are less sensitive to the Chinese military presence in the Taiwan Strait but have become more supportive of de jure independence after seeing the US aircraft in the area. Our findings contribute to studies of cross-Strait relations and US foreign policy on the Taiwan Strait.