During the 1920s and 30s, Dutch passenger liners carried thousands of travelers between Europe, the Middle East, India, and Southeast Asia. The peaceful images presented to European tourists in colorful brochures, however, overlooked the ways passenger ships embodied imperial instabilities and reflected the varied and confusing relationships between metropole and colony. The ship, therefore, became a colonial classroom where Europeans were taught to interact with non-Europeans in ways that exported terrestrial structures of empire across global maritime networks. Onboard Dutch passenger liners, segregation was essential in establishing and maintaining imperial norms around race, class, religion, and gender and shipping companies tightly regulated maritime spaces in the hopes that European passengers would transition from the disparate identities of the metropole into a consenting and unified group while at sea. Colonial ideologues assumed that if tourists learned how to maintain order through hierarchies, segregation, routines, and etiquette onboard, they would reinforce colonial norms after arriving in the colony or metropole. Europeans were able to practice their impending terrestrial roles through interactions with the ship’s Indonesian staff of stewards and nannies and officers encouraged the “viewing” of non-European travelers in the third class. At stake in this struggle between the implementation and transgression of boundaries was the very essence of imperial anxiety over racial mixing, sexual impropriety, and social status.