Thanks to Aminurashid bin Eksan from Ubin NParks for the heads up on the closure of the southern portion of the Coastal Boardwalk (red portion) for upgrading until 24 Oct 2015.
The other facilities at Chek Jawa will remain open during the period. That is, the Visitor Centre (House No. 1), Viewing Jetty (at House No. 1) and Mangrove boardwalk.
The Mangrove boardwalk and northern part of the Coastal boardwalk was closed earlier this year.
More about Chek Jawa on the NParks website and wildsingapore.