Ferries depart from Gateway of India from around 9:00–14:00 (return options vary); the caves are UNESCO-listed rock-cut temples—plan a half-day visit and confirm ferry times day-before.
Visit Haji Ali (island shrine reachable by causeway at low tide) and nearby Mahalaxmi Temple; Haji Ali is open across the day (confirm times and tide-related access).
Take a responsible, licensed Dharavi tour to learn about the area's industries and community; book in advance—typical cost around INR500–800 and it supports local guides.