The pier that connects the Elephanta Island with the ferry point.
A large number of daily flights are operated to Mumbai (BOM) from the rest of the main cities in India. So are the international connections to Mumbai.
Once in Mumbai head for the Gateway of India. This is prime landmark of Mumbai. It is from this point the ferry to Elephanta Island operate.
Though heavily crowded during the peak hours, Mumbai has an excellent suburban local rail network. From wherever you are in Mumbai, catch a local train to Churchgate or CST.
Both are terminal stations, so it is a bit easy to get out and get in. By the way CST (Chhatrapati Shivaji Terminus) railway station itself is a UNESCO World Heritage Site.
Ferry to Elephanta at the Gateway of India (seen on left). Seen in the backdrop is the Taj Mahal Hotel. Partially seen on the left is the Gateway of India