SG ↔ JB commuter guide
Tuas Second Link bus guide
The Second Link has its own set of Causeway Link routes. Knowing the route number matters because different buses continue to different Singapore and Johor destinations after immigration.
Main cross-border route pattern
Causeway Link currently lists CW3, CW4 and CW4S as services connecting through the Second Link toward Jurong East, CW6 toward Boon Lay and CW7 toward Tuas Link.
There are also Malaysia-side feeder variants that terminate at CIQ Second Link, so some journeys require a transfer rather than one continuous bus.
After immigration
Check the route number and destination board before boarding again. The correct bus after Tuas Checkpoint depends on whether you are heading to Jurong East, Boon Lay or Tuas Link.
Do not assume every Causeway Link bus at the checkpoint is interchangeable.
Who should consider Tuas
Second Link is particularly useful when your Singapore origin is in the west or your Johor destination is on the Iskandar Puteri, Bukit Indah or Gelang Patah side.
For central Johor Bahru, compare the complete travel time with Woodlands instead of comparing only the distance to the checkpoint.
Official sources
Transport and immigration rules can change. RunSGD links to official sources so you can verify requirements before travel.