No major Sri Lankan publisher has released an official, free PDF. However, you can find pre-1923 translations (public domain) on archive.org. For modern translations, you must purchase a copy.
During British colonial rule, the Kaama Sutra was deliberately mistranslated and sensationalized to portray Indians (and by extension, Sri Lankans) as "overly sexual" and uncivilized. This is why older Sinhala translations published before the 1980s often contain heavy moralizing or censorship. kaama sutra sinhala pdf
This article is for educational and informational purposes only. Always respect the laws of Sri Lanka regarding obscene publications. The author does not host or distribute any PDF files. No major Sri Lankan publisher has released an