Yes, there are plenty of Indian restaurants in Sri Lanka where a traveler can obtain vegetarian food. Some of the best Indian restaurants in Sri Lanka are:
Shanmugas, Colombo: It is one of the oldest and the most reputed Indian restaurants in Colombo. It is known for its variety of classic Indian vegetarian dishes in Colombo.
Agra, Colombo: It is another rare fine dining restaurant in Colombo and is famous for its North Indian dishes and the menu is dominated by the Mughlai cuisine.
Mango Tree, Colombo: It is one of the most popular Indian restaurants in Colombo and mainly serves North Indian dishes.
Avanhala, Kandy: This restaurant is known for its authentic Indian delicacies at cheap prices.
Sriram Indian Restaurant: It is known for both North Indian and South Indian dishes.
The Palms at Vivanta By Taj, Bentota: A luxury Indian restaurant in Bentota that offers a fine selection of scrumptious Indian dishes.