You can ride a pump boat or a fastcraft.
A passenger boat ride costs no more than hundred pesos as of November, 2018, while a fast craft ride costs ~₱300.00. Choose the latter if you want to save time.
The travel time by pump boat is 2 hours while only an hour or lesser by fastcraft.
The schedule varies. There’s a visitor center in Bancal for those needing assistance.
To return to Bancal or Estancia Port, it’s best to ask the locals in Gigantes for the schedule.
☝🏾If you have an early flight to Kalibo, Roxas or Iloilo airport, and plan to catch a joiner tour in Gigantes (usually starts at 8am or 9am), consider the possible delay of your arrival in Bancal port.