Short answer: there are not many dedicated “Jain ruins” in Sri Lanka. The ancient ruins you see there are mainly Buddhist monasteries and stupas. Historically, Jain influence did touch Sri Lanka at times (for example, in the early era of Abhayagiri Vihāra and in Mahavamsa-era accounts), but there aren’t well-known Jain temple ruins like you find for Buddhism in places such as Anuradhapura, Mihintale, or Sigiriya. Today, the famous ruins that attract visitors are predominantly Buddhist sites, not Jain.

If you’re exploring Jain-related history in Sri Lanka, you’ll mostly encounter references to Jain monks or connections in historical chronicles rather than stands of Jain temple ruins.