I am organizing a free and easy trip to bintan and i found that i cannot take the ferry from the usual Singapore Cruise Centre at harbourfront. I have to buy ferry tickets over at the other ferry terminal, the Tanah Merah Ferry Terminal (or TMFT).
You will need to take a MRT to the Tanah Merah mrt station, then change to Bus number 35 to reach the ferry terminal. The bus will take about 15 mins to reach the ferry terminal.