There is no official Grand Theft Auto: San Andreas ISO for the PSP because the game was never released for that console.
Porting Projects: Some independent developers have attempted to recreate the San Andreas map for the PSP, but these are often incomplete or "test releases" rather than the full game. 3. Alternatives and Playable Options gta san andreas iso psp link
The PSP’s GTA Legacy: The PSP actually has two phenomenal exclusive GTA games: Liberty City Stories (2005) and Vice City Stories (2006). Both run on a modified version of the San Andreas engine. Casual gamers often confuse the "Stories" titles with the mainline San Andreas. There is no official Grand Theft Auto: San
On niche forums like Wololo or GBAtemp, you may find links to homebrew experiments. These are not commercial-grade products. If you manage to get one running on a Custom Firmware (CFW) PSP, expect: PlayStation Store (PSN): https://store
It is important to clarify that Grand Theft Auto: San Andreas
PS Vita Homebrew: If you have a hacked PlayStation Vita, there is a high-quality community port of the Android version of San Andreas that runs natively on that hardware, but this is not compatible with a standard PSP.
due to the technical limitations of the UMD disc capacity and hardware at the time. Authentic Fan Projects & ISOs