Can I hike the Knuckles Mountain Range unguided?

No, going through the Knuckles Mountain Range unguided is strictly illegal and honestly pretty hazardous, because there is a dense forest, the weather shifts quickly, and you have a serious chance of getting lost. The Sri Lankan Forest Department requires that all trekkers be accompanied by a registered local guide, no exceptions.

Also, the Knuckles Conservation Forest is a heavily protected UNESCO World Heritage area; it shelters fragile biodiversity, endemic species, and a bunch of hidden dangers. Since the paths are rarely marked and thick mist can arrive within minutes, fully blocking the view, trying to figure it out on your own regularly ends with travellers needing an emergency rescue.