1. Download your own AAX files (using the Audible download manager or search around for some ways to do it w/o the download manager). 2. Find out your 'activation keys' using ffprobe and the inAudible-NG project, see instructions here: https://github.com/inAudible-NG/tables/blob/master/README.md. Needs to be done only once for your Audible account. 3. Use ffmpeg with --activation_bytes to convert AAX to MP3 or other formats, either directly or with a nice script like this one that'll divide into chapters: https://github.com/KrumpetPirate/AAXtoMP3

OpenAudible looks like a nice tool that'll automate all of these steps for you.

There are a variety of DRM Free audiobook providers:

https://www.downpour.com https://libro.fm

Most titles on audiobooksnow.com are free as well, but not quite all, so make sure there's no "DRM Protected" symbol.

I bounce between these providers (subscribing and cancelling to their various plans as needed) based on book availability and price. I believe I pay slightly less overall than if I used Audible for everything, even if acquiring books takes more work.

In a pinch, you can also remove Audible DRM with various tools (see sibling comment), but we should support proper DRM Free providers wherever possible!

This Q&A is relevant: https://askubuntu.com/questions/16918/how-to-listen-to-audib...

The second answer (which is the top voted one) is my answer. It's basically using ffmpeg with -codec copy.