Crunchyroll Dual Subs by AndyNoob

Crunchyroll Dual Sub (source here)

Web extension created to fix the annoying issue of not being able to use English and English [CC] subtitles at the same time. The extension is still in development but is guaranteed to work on shows such as One Piece where there are both types of subtitles. This extension supports Croptix and Improve Crunchyroll.

How it works

When the Crunchyroll watch page is loaded, the extension intercepts and reads your profile for your preferred/selected subtitle language and type (if you don't have one set via the drop-down). The extension retrieves the episode's subtitle data in the same manner. The alternate subtitle will then be loaded and rendered accordingly by the extension.

The extension adds a drop-down menu for you to select your desired secondary subtitle. The choice is saved for your selected profile to the sync-ed storage (if it is enabled). As of 0.10.0, a pop-up menu is provided by the extension for scoped preference control (per season, per episode, global). In the menu, you can apply an offset to the timing of both primary and secondary subtitles.

Privacy notice

Everything stays on your computer/browser. The extension does not communicate with any external servers other than Crunchyroll's services.

Credits

While not completely vibe-coded, this project was made with the help of GPT-5.3/5.5. Prior to version 0.10.0, this project used frazy-parser by ApayRus to parse subtitle files. As of version 0.10.0, ASSJS by weizhenye is used to render ASS subtitles, and srt-vtt-parser by plussub is used to parse VTT subtitle files.