St. John's Island is part of the Sisters Islands Marine Park. The western shores of St. John's Island and of Pulau Tekukor are part of the Marine Park! And rightly so, because St. John's Island is also full of amazing marine life.
Dive Trail at the Marine Park which were recently launched.
From the NParks Press Release 15 Jul 15; (also on wildsingapore news)
The Sisters’ Islands Marine Park Public Gallery is open daily from 10am to 2.30pm on weekdays, 10am to 3.30pm on Saturdays and 10am to 5.30pm on Sundays and Public Holidays to coincide with the timings of the regular ferry services. The public gallery is a 10 minute walk from the jetty. Regular ferry services to St John’s Island from Marina South Pier are available twice on weekdays and up to five times on weekends and public holidays.
The Sisters’ Islands Marine Park Public Gallery will form a part of the Marine Park Outreach and Education Centre, which is a partnership between the National Parks Board (NParks) and the Tropical Marine Science Institute (TMSI) of the National University of Singapore.
Since August 2014, volunteers have led monthly public guided walks on Big Sister’s Island to showcase the marine biodiversity found on our shores.
From end September 2015, dive enthusiasts will be able to explore the new dive trails off Big Sister’s Island by registering with approved dive operators. The Sisters’ Islands Marine Park Dive Trails will operate with underwater signboards which serve both as station markers and underwater educational resources. Divers will also be encouraged to contribute towards the upkeep of the dive trails, for example, by helping to keep the station signboards clean using brushes provided.
More about St John's Island and the ferry to St. John's Island on the Sentosa website.