Take an early morning train from Mumbai to the Gateway of India and then a ferry ride to the Elephanta Caves. The caves are a UNESCO World Heritage site and feature rock-cut temples and sculptures dedicated to Lord Shiva. Be sure to wear comfortable shoes and carry water as there is a bit of walking involved.
Take a bus or taxi to the Kanheri Caves, located in the lush green forests of the Sanjay Gandhi National Park. The caves are known for their Buddhist rock-cut monuments and inscriptions and offer a peaceful retreat from the hustle and bustle of the city. Carry a light snack and water as there are no food outlets inside the park.
Take a train or bus to the Global Vipassana Pagoda, a majestic monument and meditation center located on a peninsula overlooking the Arabian Sea. The pagoda is a replica of the Shwedagon Pagoda in Myanmar and features the largest stone dome in the world. Enjoy the serene surroundings and attend a free 1-hour meditation session.
Take a train or bus to Chowpatty Beach, a popular beachfront in Mumbai. Stroll along the promenade, watch the sunset, and savor some street food from the local vendors. Try the famous Mumbai-style "bhel puri" and "vada pav".
If you have time, visit the Sanjay Gandhi National Park and enjoy a safari ride to spot some wildlife. Also, consider visiting the Mahakali Caves, a group of 19 rock-cut cave monuments located in the Andheri suburb of Mumbai. To maximize your fun, carry a backpack with essentials like water, snacks, sunscreen, sunglasses, camera, and a light jacket. Don't forget to negotiate the taxi fares beforehand and carry small change for the bus fares.