Yes, an NRI can generally claim a share in ancestral property in India, provided they have a valid legal entitlement to the property. Being an NRI does not by itself prevent a person from inheriting or claiming property in India.
The exact share depends on factors such as whether the property is ancestral or inherited, the applicable personal law, the family structure, and whether the property has already been legally partitioned or transferred. In Hindu families, rights in coparcenary property can arise by birth, subject to the applicable law and facts of the case.
If the family members do not agree on the division, the NRI may seek a legal partition and establish their claim through the appropriate court. Property records, previous title documents, family records, and succession documents may be important evidence.
Because inheritance and ancestral-property rights can depend heavily on the property's history and the applicable personal law, an NRI should have the documents reviewed by a qualified Indian property lawyer before signing any relinquishment, partition, or settlement deed.