This article centers cross-border solidarity in the post–War of the Pacific (1879–83) context in Peru and Chile. I examine the ways in which some maritime and port workers in these countries in the early twentieth century created bonds of solidarity despite the reigning nationalism of the day. The article analyzes labor struggles and the move toward industrial organizing in Mollendo, Peru; Chilean Industrial Workers of the World efforts at creating links with Peruvian workers; and police repression after a 1925 strike in Mollendo. I combine an in-depth view of local organizing with the transnational political moves and connections forged by maritime and port workers. They lived and organized in their own ports while also forming bonds with other working-class people in the shared space of the Pacific littoral. Their organizing locally and transnationally challenged the chauvinistic nationalism of the era.