INS Kursura (S20) was a Kalvari-class diesel-electric submarine of the Indian Navy. She was India's fourth submarine. Kursura was commissioned on 18 December 1969 and was decommissioned on 27 February 2001 after 31 years of service.
She participated in the Indo-Pakistani War of 1971, where she played a key role in patrol missions. She later participated in naval exercises with other nations and made many goodwill visits to other countries.
After decommissioning, she was preserved as a museum for public access on Ramakrishna Mission Beach in Visakhapatnam. Kursura has the distinction of being one of the very few submarine museums to retain originality and has been called a "must-visit destination" of Visakhapatnam. Despite being a decommissioned submarine, she still receives the navy's "Dressing Ship" honour, which is usually awarded only to active ships.