In-package radio frequency (RF) waveguides as high bandwidth chip-to-chip interconnects and methods for using the same are disclosed. In one example, an electronic package includes a package substrate, first and second silicon dies or tiles, and an RF waveguide. The first and second silicon dies or tiles are attached to the package substrate. The RF waveguide is formed in the package substrate and interconnects the first silicon die or tile with the second silicon die or tile.