This paper presents several conditioned sound changes in the Rapanui language: replacement of rhotics with glottal stops in the final syllable, further loss of glottal stops in polymoraic words, retention of Proto-Polynesian *h in certain phonetic contexts, metathesis of consonants in adjacent syllables, dissimilation of velar nasals in the vicinity of velar stops, and assimilation of central and back vowels. The sound changes under discussion systematically distinguish between bimoraic and polymoraic lexical roots and some of them also distinguish between lexical and grammatical morphemes. Some of the sound changes are recent and operate on borrowings from Tahitian and European languages. This paper also provides new information on the phonology of Rapanui and, by extension, the Eastern Polynesian subgroup. The findings imply that, in the case of Rapanui, a phonological description would not be satisfactory without an account of productive recent and on-going sound changes.