We propose and experimentally demonstrate the implementation of lithography-free nanoapertures on optical fibers. By sputtering metallic nanofilms onto the end face of step index fibers that contain central nanochannels, fiber-integrated nanoapertures are instantaneously implemented without the use of any kind of lithographic step. In accordance with simulations, the experiments show diffraction-limited nanospots in the far-field at the location of the nanoaperture for sufficiently thick films. We reproducibly implement a series of devices by sputtering Al and Pt nanofilms, reaching aperture diameters as small as 40 nm and showing spectrally broadband operation. Due to its simplicity, scalability, and potential for large-scale production the nanoaperture enhanced fiber concept will be highly relevant for lab-on-a-fiber applications and for the development of future fiber-based nanoprobes with high spatial resolutions.