From Larkin, take Maju Pontian Express 96. Alternatively, take
South Johore express services. It is an express service, but
sometimes, it will stop along Skudai to pick up some passengers, as
for return trip, sometimes along Pekan Nenas. I believe you would
prefer express service, normal service can make your butt very pain
upon reaching Pontian. There's no direct bus link from Kotaraya to
Pontian.
Bus departs every 30-45 minutes, depends on the passenger load
basis. Fare for express service is RM4.00 or RM3.80, differs from
operator to operator.