Oh, yes — there’s a surprisingly big ecosystem for Spanish audiobooks online, and I get a little geeky about how many routes you can take.
If you’re looking for professionally narrated versions of PDF books, the first thing I do is hunt by title plus the word 'audiolibro' or search the ISBN. Big stores and services like Audible, Storytel, Apple Books, Google Play Books and Kobo often have Spanish audiobook editions for popular titles — classics like 'Cien años de soledad' and modern hits like 'La sombra del viento' frequently show up. Public library systems are gold too: in Spain, eBiblio offers both ebooks and audiobooks; in many other countries OverDrive/Libby or Hoopla will get you access for free with a library card.
If you own a PDF but there isn’t a published audiobook, text-to-speech (TTS) is an easy fallback. I use things like Voice Dream Reader on iOS, @Voice Aloud Reader on Android, Balabolka on Windows, or the Read Aloud extensions and Microsoft Edge's Read Aloud to get surprisingly natural voices (the new neural voices are neat). For public-domain Spanish works, Librivox and YouTube have volunteer or community-produced recordings you can grab legally. Just watch DRM: if your PDF is from a store, rights for audio might be separate, so converting copyrighted files and distributing them is a no-go. For my own study books I convert to MP3 or M4B for listening on the go, and I sync progress via apps that support bookmarks — it makes commute time feel like my private mini-university.