From the NParks website: "Thank you for your support for the intertidal guided walks over the past 5 years. As part of efforts to review the outreach and educational activities offered on the island, we are ceasing NParks-led guided walks at Big Sister’s Island."
NParks also added:
"Meanwhile, you can sign up for the free guided walks on St John’s Island held on the first Sunday of every month, or download a copy of the DIY trail guide and explore St John’s Island and the Marine Park Outreach and Education Centre at your leisure. Alternatively, you can check out the guided tours at Chek Jawa, Pulau Ubin."
For a look back at the guided walks, check out the Sisters Islands Marine Park facebook page.
For MORE intertidal guided walks and other shore activities, check out Celebrating Singapore Shores.