Thailand appeared to be under a tide of youthful revolutionary change. In 2020, in a rare moment in Thai history, university and secondary school students, particularly female and LGBTQ + schoolchildren, took the lead in national protests against an autocratic government. It was a period during which the seemingly impossible, such as the reform of Thailand's royal institutions, appeared possible. What were the historical origins of the country's revolutionary youth movement? This article argues that the Thai youth movement emerged from youth activist networks fostered by post-coup political entrepreneurs. It describes the foundational moments of these networks and analyses their inside brokerage processes, i.e. how these political entrepreneurs cultivated friendships and ties among segregated young activists by creating unique spaces – campsites and activist houses. These underground spaces allowed activists to connect, learn, brainstorm, organize mobilization, and build cross-issue and cross-regional activist ties under an autocratic regime. [ABSTRACT FROM AUTHOR]