Singapore Buses route 138

Service 138 is a trunk route running from Ang Mo Kio and looping at Mandai Lake Road (Singapore Zoo), going via Ang Mo Kio Avenue 3, 6 and 5, Upper Thomson and Mandai Road. It also supplements bus connections from Ang Mo Kio Avenue 5 to the Ang Mo Kio Town Centre.

It is one of the pioneer route to use Mercedes-Benz O530 Citaro, and it is the last to use Mercedes-Benz O405 (DM).

Demand for this route to and from Mandai Lake Road is high from tourists and locals alike, and concentrated around mornings, afternoons, evenings and late nights in conjunction with the opening hours of Singapore Zoo, Night Safari and River Safari. During weekends, additional spare single decker buses will be deployed to cater to the higher demand, as well as the deployment of service 138A as a shortworking trip, which allow buses to return to the Ang Mo Kio Interchange more quickly to pick up an additional load of passengers.