As of 2025, there is no complete, 100% patch for the PSP version. However, there is a significant partial patch created by a team known as "Team School Days" (formerly associated with the now-defunct School Days Translation Project).
What the patch currently includes:
The caveat: The infamous final chapters (4-6) and the bad endings remain in raw Japanese. For the full story, many players still rely on the PC version (which has a complete English patch via School Days HQ on Steam). However, for the portable experience, the partial patch is enough to grasp the core mechanics and initial drama. School Days Iso Psp English
You need a PSP 1000, 2000, 3000, or PSP Go running a Custom Firmware (CFW). With CFW, you simply copy the patched .ISO file to the ms0:/ISO/ folder on your Memory Stick. As of 2025, there is no complete, 100%