Loop Services

Loop routes (or circular routes) are a unique form of bus routing. As its name suggests, a loop route only has one terminus, unlike bidirectional routes or unidirectional routes with no return trips. Buses leave the terminus and complete their route by returning back to the same terminus. Loop routes provide continuous bus service along a longer stretch of road compared to an ordinary bidirectional route. Technically, passengers can pay a fare for the full route, ending up at the bus terminus. However, some exceptions do exist, and passengers may be required to alight at the looping point.

The point where a loop service turns back towards its starting point (and merges with its own forward route), is known as a looping point. After the looping point, buses resume their return route back to the bus terminus. Looping points can be named after street names (e.g. Changi North Crescent) or places of interest near the looping point (e.g. Singapore Zoo). However, not all loop routes have a defined looping point.

Some special cases do exist with loop routes. For example, some bidirectional trunk routes operate like loop routes, and drivers do not park their buses nor get a layover at the bus terminal. Some loop routes have multiple looping points, and some have looping points within restricted areas.

Some loop services have their Electronic Display Systems (EDS) programmed with both directions of the loop route, and bus drivers will switch the directions on their EDS at the looping point. Some other services, e.g. 4 and 116, have an EDS display of both the terminus and the looping point, hence eliminating the need for switching the EDS. On older buses, drivers have to manually flip their side destos by removing them out of the desto holder and putting them back in. This was because both sides of the desto was printed with route details. This practice was phased out with the retirement of square destos.

In this article, a forward route refers to heading away from the terminus, while a return route refers to heading back towards the terminus.

Listed below are a few types of loop routes in Singapore. Some bus routes may fall under multiple categories:

1. Normal loop routes

Let’s say Bob is at point A and needs bus connections to point B and C. With a normal bidirectional route passing through point B, Bob will not be able to head for point C. Similarly, with a normal bidirectional route passing through point C, Bob does not have bus connections to point B. Such loop routes solve the problem often by using different sections of road in their forward journey and return journey.


  • SBST Service 36 / 111 (Orchard Road)
  • SBST Service 125 (Sims Drive)
  • Most SBST and SMRT Feeder Bus services

2. Looping at bus interchange

Some loop routes loop at bus interchanges, without having any layover there. This is usually because they need to quickly return to their terminus without introducing unnecessary layovers, or to avoid the need for setting up a driver’s kiosk there when the bus company does not operate any other routes into that interchange.


  • SBS Transit Service 17 / 18 / 60 / 69 (Bedok Int)
  • SMRT Service 173 (Clementi Int)
  • SMRT Service 180 (Boon lay Int)
  • SMRT Service 965 (Sengkang Int)

3. Point loop routes

Let’s have a service from point A and looping at point B. Because of geographical limitations (e.g. no space for a bus terminus) or for various operational reasons when the bus should return to point A as quickly as possible, the service will be operated as a loop route. Point loop routes routes are characterized by a single looping point (e.g. a roundabout / three point turn) and heavy duplication of their forward and return journeys. Most loop routes in Singapore fall under this category.


  • SBST Service 15 (Marine Parade)
  • SBST Service 35 (Airport Logistics Park)
  • SBST Service 84 (Punggol Road End)
  • SBST Service 98 (Jurong Island Checkpoint)
  • SBST Service 158 (Tanjong Rhu Cross)
  • SBST Service 183 (Science Park Road)
  • SMRT Service 882 (Sembawang Park)
  • SMRT Service 926 / 927 (Singapore Zoo)
  • SMRT Service 966 (Marine Parade)
  • Some SBST and SMRT Feeder Bus services

4. Area loop routes

Let’s have a service from point A and looping at point B. Because of geographical limitations (e.g. no space for a bus terminus) or for various operational reasons when the bus should return to point A as quickly as possible, the service will be operated as a loop route. Area loop routes do not loop around a point, but over an small area instead, using multiple turns at various junctions. They are characterized by heavy duplication of their forward and return journeys. Most loop routes in Singapore fall under this category.


  • SBST Service 4 (Changi North Way)
  • SBST Service 23 (Little India)
  • SBST Service 24, 27, 34, 36, 53, SMRT 858 (Changi Airport)
  • SBST Service 55 / 135 / 155 (Siglap Road)
  • SBST Service 70M / 107M / 111/ 162M (Suntec City)
  • SBST Service 96 (NUS)
  • SBST Service 179, 199 (NTU)
  • SBST Service 182/182M (Tuas South Avenue 9)
  • SBST Service 401 (ECP Service Rd)
  • SBST Express 502 / 518 (City)
  • SMRT Service 925C (Neo Tiew)
  • Most SBST and SMRT Feeder Bus services

5. Clockwise/Anticlockwise loop routes

In some situations, a loop route will be required to connect points A, B and C. An ordinary loop route going through A, B and C in order may face some problems. For example, there may be high passenger demand from B to A, as well as from C to A. This creates overcrowding on the route, as well as unnecessary travel time for passengers at B. Also, although passengers at B will be able to alight at C, passengers at C will not have bus connections to B. This is when clockwise and anticlockwise loop routes are launched, one routed as ABCA and the other routed as ACBA, to cater to the needs of different commuters.


  • SBST Feeder 225G/225W
  • SBST Feeder 410G/410W

6. Two-part loop routes

Some loop routes are actually two loop routes combined into one, and the route stops at the original terminus midway through the route. Both the first and second leg serve different areas (ABACA). This system allows passengers to travel between the areas served by both legs of the route. This is most commonly seen in intratown/townlink routes. To differentiate between the two legs of the route, SBS Transit used to implement a red/green plate system for the two legs.


  • SBST Townlink 291 and 293
  • SBST Townlink 358 and 359
  • SMRT Intratown 811 and 812
  • SMRT Intratown 911, 912 and 913

For SBST Townlink services, the driver will place a T sign at the front of the bus during the second leg if the bus will terminate at the interchange. Otherwise, the bus will continue on its second trip (i.e. first leg again) after finishing the second leg. For SMRT Intratown services, a letter E will be added at the back of the route number (e.g. 812E). Drivers do two rounds (i.e. 4 legs) of the service before going for their break.

7. “Infinite” loop routes

This variant of loop routes allow passengers to remain onboard the bus at the bus terminus. The passengers can wait onboard until the bus departs on its next trip. The distance fare will be accumulated for both stretches of route (return and forward trip) once the passenger taps out, or a passenger pays a cash fare equivalent to the distance he traveled. This form of loop route technically allows passenger to stay onboard for as long as they like, as the fare will only be charged upon alighting ( A)


  • SBST Service 36 (Changi Airport PTB2)
  • SBST Service 92 (Ghim Moh Ter)

8. Looping point within restricted areas

Some routes loop within restricted areas where a pass is needed to enter. Such is the case for Changi Airfreight Terminal, where only workers with a valid entry pass can enter the restricted area. For card-paying passengers, their ride will be suspended upon tapping out at the Police Pass Office, and resumed upon boarding the same service as they alighted (at another bus stop near the Police Pass Office after buses exit the restricted areas). For cash paying passengers, they will have to pay again upon boaring if their ticket expires within the restricted area. (A→B→C→B→A)


  • SBST Service 9
  • SBST Service 19
  • SBST Service 89

9. Loop routes not operating from bus terminals

These routes are implemented without bus terminals and originate / terminate from various enroute bus stops


  • SBST Service 42 (Jln Kembangan)
  • SBST Service 53M
  • SBST Service 115 (Hougang Street 21)

10. Loop routes operating like trunk routes

Some routes are designated as loop routes but operate like trunk routes. They have a terminus at either end and have a short layover at the looping terminus, usually without any driver’s kiosk.


  • SBST Service 63 (Rumah Tinggi)
  • SMRT Service 975 (Lim Chu Kang Road End)

11. Trunk routes operating like loop routes

Some routes are designated as trunk routes but operate like loop routes. Drivers do not take a layover break at the looping terminus, they simply alight all passengers and proceed to pick up passengers for the return journey.


  • SBST Service 159
  • SBST Service 163
  • SMRT Service 177 (Before BPJ Temp)
  • SBST Service 192
  • SBST Service 193
  • SMRT Service 856

Do note that the above classification is not exclusive, and various bus services can fall under multiple classifications.


Poster at Bedok Interchange

Bus route details for Service 17, which loops inside Bedok (Temporary) Bus Interchange. Notice how it is written that the service loops at Bedok Nth Drive, and the interchange is used as an enroute stop.

Thank you for visiting this article! Do check out our other bus articles by clicking here.

Tl;dr for you, a reference for the rest of us!

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