The incident occurred in afternoon when altogether 18 students ventured into the sea to swim.
The students, aged between 18 and 20, were undergoing BSC and BCA computer courses.
According to a Coast Guard spokesperson, 13 bodies were recovered while a few students are still untraced and the Coast Guard and Navy have launched operations to rescue some missing students.
The students were part of an around 126-strong group from Inamdar College in Pune who went to Murud in three buses for a picnic.
He said at least six students were taken to hospital.
The Navy has also deployed two interceptor craft for the search operations.
P A Inamdar, Trustee of the Pune-based college, run by Maharashtra Cosmopolitan Education Society, has confirmed that 13 students died in the mishap.
He alleged that the beach where the students had gone apparently had no life guard.
The picnickers were accompanied by around ten staff members including teachers, the college authorities said.
Inamdar said the college has received names of the deceased but their parents would be informed only after confirming and establishing their identities by checking the respective rolls.
A team of college officials has left for Murud to assist rescue work.
