History of Services 131 - 140

Service 131

Operator	Route	Year	Date	Service changes
STC	Balestier Rd ↔ Tg Pagar Rd (1971 - 1978)	1971	11 April	Introduced between Balestier Rd Ter and Tg Pagar Ter under 1971 Bus Reorganisation.
ABS			6 December	Operations transferred to ABS.
		1974	8 December	Amended to ply Cecil St, skipping Robinson Rd.
		1975	19 July	Amended to ply Coleman St and Armenian St, skipping Stamford Rd.
	Tg Pagar Rd ↺ Balestier Rd (1978 - 1979)	1978	2 December	Amended to ply Balestier Rd, Jln Dusun and Jln Datoh due to the partial closure of Ah Hood Rd for redevelopment.
		1979	11 February	Amended to ply the extended Shenton Way, Rambau St and Trafalgar St towards Tg Pagar Ter, skipping Parsi Rd.
	Anson Rd ↺ Balestier Rd (1979 - 1983)		1 August	Amended to Anson Rd Ter.
	Anson Rd ↺ Rangoon Rd (1983 - 1985)	1983	2 January	Amended to loop at Norfolk Rd from Anson Rd Ter.
			3 July	Amended to ply Kent Rd and Owen Rd with the partial closure of Rangoon Rd to facilitate the construction of CTE.
	Prince Edward ↺ Rangoon Rd (1985 - 1987)	1985	27 January	Amended to Prince Edward Ter with the closure of Anson Rd Ter.
		1987	7 June	Amended to ply Owen Rd, Dorset Rd, Kg Java Rd, Bt Timah Rd and Sungei Rd, skipping Race Course Rd, Kerbau Rd, Kg Kapor Rd, Upp Weld Rd and Jln Besar.
	Shenton Way ↺ Rangoon Rd (1987 - 1992)		28 June	Amended to Shenton Way Ter.
	Shenton Way ↔ St. Michael's (1992 - 1993)	1992	3 May	Extended to St. Michael's Ter under TransitLink Network Integration Exercise Phase 7.
	Bukit Merah ↔ St. Michael's (since 1993)	1993	4 April	Extended to Bt Merah Int under TransitLink Network Integration Exercise Phase 12.
			11 April	Amended to ply Stamford Rd, skipping Coleman St and Armenian St.
		1999	TBC	Skips a pair of removed bus stops outside and opposite Wishart Rd along Telok Blangah Rd.
			TBC	Serves new bus stop outside Farrer Pk Tennis Ctr along Dorset Rd.
		2001	18 February	Serves new staggered bus stop outside Novena Stn along Thomson Rd, skipping the bus stop outside Novena Ch.
Template:SBS Transit (Current)		2005	19 June	Amended to ply Bt Purmei Ave in both directions.
		2006	29 October	Serves new bus stop outside VivoCity along Telok Blangah Rd.
		2007	28 April	Serves additional bus stop outside Victoria Concert Hall along Fullerton Rd.
		2008	7 December	Skips removed bus stop opposite Temenggong D Mque along Telok Blangah Rd.
		2011	16 October	Amended to ply Middle Rd, Selegie Rd, Prinsep St and Bras Basah Rd with the partial closure of Bencoolen St to facilitate the construction of Bencoolen MRT station on the Downtown MRT Line.
			3 December	Designated wheelchair-accessible bus service (WAB).
		2014	25 August	Last bus from Bt Merah Int extended to 2400 hrs daily.
		2016	1 May	Amended to ply Esplanade Dr towards St. Michael's Ter with the partial closure of Fullerton Rd.
			11 December	Amended to ply the reinstated Bencoolen St, skipping Middle Rd, Selegie Rd, Prinsep St and Bras Basah Rd.
		2021	26 December	Amended to ply Esplanade Dr towards Bt Merah Int with the closure of Connaught Dr.

Short Trip 131A

Operator	Year	Date	Service changes
Template:SBS Transit (Current)	2002	TBC	Introduced from St. Michael's Ter to Shenton Way (Opp Temasek Twr) during morning peak hours on weekdays.
	2011	16 October	Amended to ply Middle Rd, Selegie Rd, Prinsep St and Bras Basah Rd with the partial closure of Bencoolen St to facilitate the construction of Bencoolen MRT station on the Downtown MRT Line.
		3 December	Designated wheelchair-accessible bus service (WAB).
	2016	11 December	Amended to ply the reinstated Bencoolen St, skipping Middle Rd, Selegie Rd, Prinsep St and Bras Basah Rd.
	2021	26 December	Amended to ply Esplanade Dr with the closure of Connaught Dr.

Short Trip 131B (January - June 2006)

Operator	Year	Date	Service changes
Template:SBS Transit	2006	23 January	Introduced as a short-trip service from Serangoon Rd (Tekka Ctr) to Norfolk Rd (Bef Carlisle Rd) during evening peak hours on weekdays.
		1 June	Discontinued.

Service 131M (2014 - 2022)

Operator	Year	Date	Service changes
Template:SBS Transit	2014	25 August	Introduced between Bt Merah Int and Bt Purmei Ave (Loop) as a peak hour variant of Service 131 on weekdays, replacing Service 275. Wheelchair-accessible at launch.
	2022	12 December	Discontinued.

Service 132

Operator	Route	Year	Date	Service changes
	Ang Mo Kio Ave 6 ↺ Orchard Rd (1978 - 1979)	1978	9 October	Introduced between Ang Mo Kio Ave 6 Ter and Orchard Rd (Loop).
	Ang Mo Kio ↺ Orchard Rd (1979 - 1984)	1979	12 August	Amended to Ang Mo Kio Ave 3 Ter.
		1981	5 July	Amended to Ang Mo Kio Ctrl 2 Ter.
		1983	10 April	Amended to Ang Mo Kio Int.
	Ang Mo Kio ↔ Bukit Merah (1984 - 1988)	1984	29 January	Extended to Bt Merah Int.
		1986	16 November	Serves new staggered bus stop outside Thong Teck Bldg along Scotts Rd, skipping the bus stop outside Metro Orchard.
	Hougang South ↔ Bukit Merah (1988 - 2004)	1988	18 December	Extended to Hougang Int.
		1990	21 February	Skips removed bus stop opposite Jasmine Rd along Upp Thomson Rd.
			27 May	Serves additional bus stop outside Police Academy along Whitley Rd.
		2000	4 June	Serves new pair of bus stops outside and opposite British High Comm along Tanglin Rd.
Template:SBS Transit (Current)	Hougang Ctrl ↔ Bukit Merah (since 2004)	2004	15 February	Amended to Hougang Ctrl Int with the closure of Hougang Sth Int.
		2013	31 March	Designated wheelchair-accessible bus service (WAB).
		2020	8 November	Skips the bus stop opposite SLF Cplx along Thomson Rd to facilitate the construction of the North-South Corridor (NSC).
		2023	23 July	Amended to ply temporary slip road and Mt Pleasant Rd with the temporary closure of slip road to PIE Exit 17D, serving new staggered bus stop after Mt Pleasant Rd along Thomson Rd.

Service 132A (1984 - 1986)

Operator	Year	Date	Service changes
	1984	30 January	Introduced between Ang Mo Kio Int and Tomlinson Rd (Loop) as a peak hour service on weekdays & Saturdays.
	1986	14 April	Discontinued.

Service 133

Operator	Route	Year	Date	Service changes
	Ang Mo Kio Ave 6 ↺ North Bridge Rd (1978 - 1980)	1978	29 December	Introduced between Ang Mo Kio Ave 6 Ter and Nth Bridge Rd (Loop).
	Ang Mo Kio ↺ North Bridge Rd (1980 - 1987)	1980	6 January	Amended to Ang Mo Kio Ave 3 Ter.
		1981	5 July	Amended to Ang Mo Kio Ctrl 2 Ter.
		1983	6 February	Amended to ply CTE towards Ang Mo Kio Ctrl 2 Ter with the closure of temporary slip road between Braddell Rd and Lor Chuan.
			10 April	Amended to Ang Mo Kio Int.
			20 June	Amended to ply CTE towards Nth Bridge Rd.
	Ang Mo Kio ↔ Marina Ctr (1987 - 1997)	1987	26 July	Extended to Marina Ctr Ter.
		1989	5 November	Amended to ply Ang Mo Kio Ave 1, Boundary Rd, Serangoon Ave 2 and Upp Serangoon Rd, skipping CTE.
	Ang Mo Kio ↺ Temasek Ave (1997 - 2010)	1997	23 March	Amended to loop at Temasek Ave and amended to ply Kallang Rd and Victoria St, skipping Crawford St and Nth Bridge Rd.
		2000	TBC	Last bus extended to 2345 hrs on Saturdays.
Template:SBS Transit (Current)		2002	24 March	Amended to Ang Mo Kio Temp Int.
			TBC	Serves new pair of bus stops after Sommerville Rd and after Sunshine Lodge along Upp Serangoon Rd.
		2003	20 June	Serves new pair of bus stops outside Potong Pasir Stn along Upp Serangoon Rd.
		2007	28 April	Amended to Ang Mo Kio Integrated Transport Hub.
	Ang Mo Kio ↔ Shenton Way (since 2010)	2010	26 April	Extended to Shenton Way Ter.
		2011	26 September	Designated wheelchair-accessible bus service (WAB).
		2012	14 January	Serves relocated bus stop after Marina St along Marina Stn Rd.
		2013	29 December	Amended to ply Central Blvd and Shenton Way with the opening of MCE.
		2014	28 September	Amended to ply Robinson Rd and Marina Blvd towards Ang Mo Kio Int, skipping Maxwell Rd and Central Blvd with the road changes in Marina Sth area.
		2017	25 June	Amended to the relocated Shenton Way Ter.

Service 133A (1988 - 1989)

Operator	Year	Date	Service changes
	1988	10 July	Introduced between Ang Mo Kio Int and Marina Ctr Ter as an alternate route of Service 133 via Boundary Rd and Serangoon Ave 2.
	1989	5 November	Integrated with Service 133 and discontinued.

Short Trip 133A (2000 - 2010)

Operator	Year	Date	Service changes
	2000	TBC	Introduced from Ang Mo Kio Int to Raffles Ave (Opp Marina Sq) during morning peak hours on weekdays.
Template:SBS Transit	2002	24 March	Amended to Ang Mo Kio Temp Int.
		TBC	Serves new bus stop after Sunshine Lodge along Upp Serangoon Rd.
	2003	20 June	Serves new bus stop outside Potong Pasir Stn along Upp Serangoon Rd.
	2007	28 April	Amended to Ang Mo Kio Integrated Transport Hub.
	2010	26 April	Discontinued.

Service 133M (2010 - 2012)

Operator	Year	Date	Service changes
Template:SBS Transit	2010	26 April	Introduced between Shenton Way Ter and Temasek Ave (Loop).
		4 October	Revised to operate on Saturdays, Sundays and Public Holidays only.
	2011	26 September	Designated wheelchair-accessible bus service (WAB).
	2012	26 May	Discontinued.

Service 134 (1980 - 1993)

Operator	Year	Date	Service changes
	1980	17 August	Introduced between Ang Mo Kio Ave 3 Ter and New Bridge Rd Ter.
	1981	5 July	Amended to Ang Mo Kio Ctrl 2 Ter.
	1983	10 April	Amended to Ang Mo Kio Int.
	1987	6 June	Amended to the relocated New Bridge Rd Ter.
		27 September	Amended to ply the extended Eu Tong Sen St towards Ang Mo Kio Int to facilitate the first stage of road expansion along New Bridge Rd.
		1 November	Amended to ply Eu Tong Sen St towards Ang Mo Kio Int to facilitate the second stage of road expansion along New Bridge Rd.
	1988	20 March	Amended to ply Upp Cross St and New Bridge Rd, skipping Neil Rd.
	1992	3 May	Shortened to Bishan Int under TransitLink Network Integration Exercise Phase 7.
	1993	11 April	Amended to ply Hill St and New Bridge Rd, skipping Nth Bridge Rd, Sth Bridge Rd and Upp Cross St.
		5 December	Integrated with Service 104 to form Service 54 and discontinued under TransitLink Network Integration Exercise Phase 14.

Service 134 (since 2016)

Operator	Year	Date	Service changes
Template:SBS Transit (Current)	2016	20 March	Introduced between Sims Pl Ter and Marine Terr (Loop) under the LTA's Bus Service Enhancement Programme (BSEP), operating between 0600 hrs and 2345 hrs daily. Wheelchair-accessible at launch.

Service 135

Operator	Route	Year	Date	Service changes
	Toa Payoh ↔ Bedok Rd (Feb - Nov 1974)	1974	3 February	Re-numbered from Service 155A between Toa Payoh Town Ctr Ter and Bedok Rd Ter under 1974 Bus Rationalisation.
	Toa Payoh ↔ Upp Changi Rd 8¼ ms (1974 - 1980)		10 November	Amended to Upp Changi Rd 8¼ ms (13.3 km) Ter.
		1975	2 March	Amended to ply Sims Ave towards Bedok Rd Ter with the conversion of Geylang Rd to one-way traffic.
		1976	18 July	Amended to skip Tanah Merah Besar Rd and Nicoll Dr on Sundays and Public Holidays.
			30 December	Amended to ply Sims Ave/Geylang Rd and the extended Tg Katong Rd, skipping Guillemard Rd.
		1979	TBC	Relocated to Upp Changi Rd 15.5km Ter.
	Toa Payoh ↔ Somapah Depot (1980 - 1981)	1980	16 June	Amended to Somapah Depot.
			28 December	Amended to ply Upp Changi Rd East, skipping Upp Changi Rd.
	Toa Payoh ↔ Marine Parade (1981 - 1983)	1981	21 June	Shortened to Marine Parade Ter.
	Marine Parade ↺ Circuit Rd (1983 - 1987)	1983	26 December	Shortened to loop at Circuit Rd from Marine Parade Ter and amended to ply Marine Parade Rd, skipping East Coast Rd.
	Marine Parade ↔ Ang Mo Kio (1987 - 2001)	1987	19 April	Extended to Ang Mo Kio Int.
		1994	TBC	First bus from Marine Parade Ter brought forward to 0545 hrs on weekdays and Saturdays.
	Ang Mo Kio ↺ Siglap Rd (2001 - 2021)	2001	16 September	Amended to loop at Siglap Rd from Ang Mo Kio Int with the closure of Marine Parade Ter.
Template:SBS Transit (Current)		2002	24 March	Amended to Ang Mo Kio Temp Int.
			TBC	Serves new pair of bus stops after Sommerville Rd and after Sunshine Lodge along Upp Serangoon Rd.
		2003	16 March	Amended to ply Eunos Ave 5 and Eunos Rd 8 with the partial closure of Paya Lebar Rd to facilitate the construction of Paya Lebar MRT station on the Circle MRT Line.
			TBC	Serves new bus stop outside Victoria Sch along Marine Parade Rd.
			TBC	Serves new bus stop outside Shell Kiosk along Tg Katong Rd.
		2007	28 April	Amended to Ang Mo Kio Integrated Transport Hub.
		2009	23 August	Amended to ply the reinstated Paya Lebar Rd, skipping Eunos Ave 5 and Eunos Rd 8.
			22 November	Serves new bus stop opposite MacPherson Stn along Circuit Lk.
		2011	7 March	Designated wheelchair-accessible bus service (WAB).
			26 June	Amended to ply Lor Bengkok with the closure of Circuit Lk to facilitate the construction of MacPherson MRT station on the Downtown MRT Line.
		2016	16 October	Amended to ply the reinstated Circuit Lk, skipping Lor Bengkok.
		2017	12 March	Amended to ply Upp Serangoon Rd and the diverted Upp Aljunied Rd.
		2018	23 September	Amended to ply ECP and Bedok Sth Ave 1 with the partial closure of Siglap Lk to facilitate the construction of Siglap MRT station on the Thomson-East Coast MRT Line.
		2020	22 March	Amended to ply the reinstated Siglap Lk, skipping ECP and Bedok Sth Ave 1.
	Ang Mo Kio ↔ Kembangan Stn (since 2021)	2021	28 February	Amended to terminate at Jln Kembangan (Kembangan Stn) via Telok Kurau Rd, East Coast Rd and Frankel Ave and converted to bi-directional service, skipping Siglap Rd and a portion of Marine Parade Rd.

Short Trip 135A (2001 - 2021)

Operator	Year	Date	Service changes
	2001	16 September	Introduced from Ang Mo Kio Int to Siglap Rd (Opp Mandarin Gdns), operating after the last bus of Service 135 daily.
Template:SBS Transit	2002	24 March	Amended to Ang Mo Kio Temp Int.
	2003	16 March	Amended to ply Eunos Ave 5 and Eunos Rd 8 with the partial closure of Paya Lebar Rd to facilitate the construction of Paya Lebar MRT station on the Circle MRT Line.
		TBC	Serves new bus stop outside Shell Kiosk along Tg Katong Rd.
	2005	TBC	Extended to terminate at Marine Parade Rd (Victoria Sch).
	2007	28 April	Amended to Ang Mo Kio Integrated Transport Hub.
	2009	23 August	Amended to ply the reinstated Paya Lebar Rd, skipping Eunos Ave 5 and Eunos Rd 8.
	2011	7 March	Designated wheelchair-accessible bus service (WAB).
		26 June	Amended to ply Lor Bengkok with the closure of Circuit Lk to facilitate the construction of MacPherson MRT station on the Downtown MRT Line.
	2016	16 October	Amended to ply the reinstated Circuit Lk, skipping Lor Bengkok.
	2017	12 March	Amended to ply Upp Serangoon Rd and the diverted Upp Aljunied Rd.
	2018	23 September	Amended to ply ECP and Bedok Sth Ave 1 with the partial closure of Siglap Lk to facilitate the construction of Siglap MRT station on the Thomson-East Coast MRT Line.
	2020	22 March	Amended to ply the reinstated Siglap Lk, skipping ECP and Bedok Sth Ave 1.
	2021	28 February	Discontinued with the amendment of Service 135 to Jln Kembangan (Kembangan Stn).

Service 136 (1974 - 1975)

Operator	Year	Date	Service changes
	1974	3 February	Re-numbered from Service 140A as a service between Toa Payoh Town Ctr Ter and Stamford Rd (Loop).
		TBC	Extended to Prince Edward Ter.
	1975	TBC	Discontinued.

Service 136 (since 1978)

Operator	Route	Year	Date	Service changes
	Ang Mo Kio Ave 6 ↔ Upp Serangoon Rd (10.5 km) (Jul - Dec 1978)	1978	27 July	Introduced between Ang Mo Kio Ave 6 Ter and Upp Serangoon Rd 10.5 km Ter.
	Ang Mo Kio Ave 6 ↺ Upp Serangoon Rd (Dec 1978 - 1980)		4 December	Extended to loop at Upp Serangoon Rd.
	Ang Mo Kio ↺ Upp Serangoon Rd (1980 - 1994)	1980	6 January	Amended to Ang Mo Kio Ave 3 Ter.
		1981	5 July	Amended to Ang Mo Kio Ctrl 2 Ter.
		1983	10 April	Amended to Ang Mo Kio Int.
		1994	TBC	Last bus extended to 2345 hrs on Saturdays.
	Ang Mo Kio ↔ Hougang Ctrl (1994 - 1996)		17 December	Amended to Hougang Ctrl Int.
	Ang Mo Kio ↺ Hougang Ave 8 (1996 - 2001)	1996	22 June	Amended to loop at Hougang Ave 8 from Ang Mo Kio Int.
	Ang Mo Kio ↺ Upp Serangoon Rd (2001 - 2002)	2001	1 January	Amended to loop at Upp Serangoon Rd.
			15 July	Amended to u-turn around Boundary Rd before proceeding to Yio Chu Kang Rd towards Ang Mo Kio Int, serving an additional bus stop outside S'pore Crocodilarium along Upp Serangoon Rd.
Template:SBS Transit	Ang Mo Kio ↺ Punggol Ctrl (2002 - Sep 2003)	2002	17 February	Extended to loop at Punggol Ctrl from Ang Mo Kio Int.
			24 March	Amended to Ang Mo Kio Temp Int.
	Ang Mo Kio ↺ Punggol Stn (Sep - Nov 2003)	2003	14 September	Amended to loop at Punggol Ctrl.
	Ang Mo Kio ↔ Punggol (since Nov 2003)		30 November	Amended to Punggol Temp Int.
		2007	28 April	Amended to Ang Mo Kio Integrated Transport Hub.
		2011	7 March	Designated wheelchair-accessible bus service (WAB).
(Current)		2016	4 September	Operations transferred to Go-Ahead Singapore.

Short Trip 136A (2002 - 2003)

Operator	Year	Date	Service changes
Template:SBS Transit	2002	17 February	Introduced from Ang Mo Kio Int to Punggol Ctrl (Opp Blk 293), operating after the last bus of Service 136 daily.
		24 March	Amended to Ang Mo Kio Temp Int.
	2003	14 September	Amended to terminate at Punggol Ctrl (Punggol Stn).
		30 November	Discontinued with the route amendment of Service 136 to Punggol Temp Int.

Service 137 (1973 - 1992)

Operator	Year	Date	Service changes
UBC	1973	25 June	Introduced between Toa Payoh Town Ctr Ter and Mandai Lake Rd (Loop).
	1980	13 July	Amended to ply Toa Payoh East, Kim Keat Ave, Toa Payoh East, Lor 7 Toa Payoh, Lor 6 Toa Payoh, Toa Payoh East, Lor 5 Toa Payoh and Lor 4 Toa Payoh.
	1983	26 December	Amended to Toa Payoh Int.
	1990	21 February	Skips removed bus stop opposite Jasmine Rd along Upp Thomson Rd.
	1992	20 September	Discontinued under TransitLink Network Integration Exercise Phase 9.

Service 137 (since 2017)

Operator	Year	Date	Service changes
Template:SBS Transit (Current)	2017	21 October	Introduced between Sims Pl Ter and Upp East Coast Ter under the LTA's Bus Service Enhancement Programme (BSEP), operating between 0600 hrs and 2330 hrs daily from Sims Pl Ter and Upp East Coast Ter. Wheelchair-accessible at launch.

Short Trip 137A

Operator	Year	Date	Service changes
Template:SBS Transit (Current)	2019	11 February	Introduced from New Upp Changi Rd (Bedok Stn Exit B) to Bedok Nth Rd (Bedok Nth Stn Exit A) during morning peak hours on weekdays. Wheelchair-accessible at launch.

Service 138 (1972 - 1974)

Operator	Year	Date	Service changes
UBC	1972	26 June	Introduced between Toa Payoh Town Ctr Ter and Jln Aman (Loop).
	1974	3 February	Discontinued under 1974 Bus Rationalisation.

Service 138 (1978 - 1988)

Operator	Year	Date	Service changes
	1978	27 July	Introduced between Ang Mo Kio Ave 6 Ter and Robinson Rd (Loop), replacing Blue Arrow Service 308.
		3 December	Amended to ply Mayne Rd and Bt Timah Rd with the partial conversion of Mackenzie Rd to two-way traffic.
	1979	11 February	Amended to ply the extended Shenton Way, Keppel Rd and Anson Rd, skipping Parsi Rd.
		12 August	Amended to Ang Mo Kio Ave 3 Ter.
		15 October	Amended to ply Marymount Rd, converted to a semi-express service operating on weekdays and Saturdays only.
		28 October	Amended to ply Sungei Rd (towards Shenton Way) and Bt Timah Rd (towards Ang Mo Kio Ave 3 Ter) with the partial conversion of Bt Timah Rd to two-way traffic and Rochor Canal Rd to one-way traffic, skipping Mackenzie Rd and Mayne Rd.
	1981	5 July	Amended to Ang Mo Kio Ctrl 2 Ter.
		11 October	Serves new staggered bus stop outside Tunas Bldg along Anson Rd, skipping the bus stop outside Intl Plaza.
		2 November	Converted to express service, calling at key bus stops along Ang Mo Kio Ave 3, Ang Mo Kio Ave 6, Anson Rd, Robinson Rd, Collyer Quay, Connaught Dr and Coleman St.
	1982	TBC	Last bus extended to 1930 hrs on weekdays & Saturdays.
	1983	10 April	Amended to Ang Mo Kio Int.
	1985	15 April	Serves all bus stops along Connaught Dr, Collyer Quay, Raffles Quay and Shenton Way and amended to ply Dhoby Ghaut, Selegie Rd, Bt Timah Rd and Kg Java Rd towards Ang Mo Kio Int.
	1986	7 January	Serves all bus stops along Marymount Rd.
	1988	24 January	Discontinued.

Service 138 (since 1994)

Operator	Route	Year	Date	Service changes
	Yio Chu Kang ↺ S'pore Zoo (Apr - Sep 1994)	1994	26 April	Introduced between Yio Chu Kang Ter and Mandai Lake Rd (Loop).
	Ang Mo Kio ↺ S'pore Zoo (since Oct 1994)		1 October	Amended to Ang Mo Kio Int.
		1996	TBC	Serves new bus stop outside Jubilee along Ang Mo Kio Ave 8.
		1997	TBC	Serves new bus stop before Mandai Rd along Mandai Lake Rd.
Template:SBS Transit (Current)		2002	24 March	Amended to Ang Mo Kio Temp Int and amended to ply Ang Mo Kio Ave 3 and Ang Mo Kio Ave 6.
		2007	28 April	Amended to Ang Mo Kio Integrated Transport Hub.
		2011	26 September	Designated wheelchair-accessible bus service (WAB).
		2018	14 October	Skips a pair of removed bus stops before and after Singapore Zoo along Mandai Lake Rd.

Short Trip 138A (June - October 2009)

Operator	Year	Date	Service changes
Template:SBS Transit	2009	22 June	Introduced from Ang Mo Kio Int to Ang Mo Kio Ave 5 (Opp Blk 604) during evening peak hours on weekdays.
		12 October	Discontinued.

Short Trip 138A (since 2012)

Operator	Year	Date	Service changes
Template:SBS Transit (Current)	2012	1 December	Introduced from Ang Mo Kio Int to Mandai Lake Rd (Singapore Zoo) on Saturdays, Sundays and Public Holidays. Wheelchair-accessible at launch.
	2018	14 October	Skips removed bus stop before Singapore Zoo along Mandai Lake Rd.

Short Trip 138B

Operator	Year	Date	Service changes
Template:SBS Transit (Current)	2015	19 October	Introduced from Ang Mo Kio Int to Ang Mo Kio Ave 5 (Opp Blk 604) during evening peak hours on weekdays. Wheelchair-accessible at launch.

Service 139

Operator	Route	Year	Date	Service changes
UBC	Toa Payoh ↔ Lengkok Bahru (1971 - 1979)	1971	21 September	Introduced between Toa Payoh Town Ctr Ter and Lengkok Bahru Ter.
			28 September	Amended to ply the extended Ganges Ave towards Toa Payoh Town Ctr Ter.
		1974	1 October	Serves merged bus stop outside Sri Srinivasa Perumal Tp along Serangoon Rd.
		1979	11 November	Amended to ply Ganges Ave towards Lengkok Bahru Ter with the realignment of Delta Circus.
	Toa Payoh ↔ Bukit Merah (since 1979)		23 December	Amended to Bt Merah Ctrl Ter.
		1980	20 January	Amended to ply the branch road of Havelock Rd towards Bt Merah Ctrl Ter.
			28 September	Amended to Bt Merah Int.
		1983	26 December	Amended to Toa Payoh Int.
		1986	2 February	Amended to ply Orchard Rd and Penang Rd towards Bt Merah Int, skipping Fort Canning Rd.
		1991	21 April	Amended to ply Bt Merah Ctrl.
		1992	TBC	Amended to ply Clemenceau Ave towards Toa Payoh Int, skipping Tank Rd.
		1993	4 April	Integrated with Service 122 and amended to ply River Valley Rd, Delta Rd and Alexandra Rd under TransitLink Network Integration Exercise Phase 12, skipping Havelock Rd, Ganges Ave, Lower Delta Rd and Tiong Bahru Rd.
		1997	29 December	Amended to ply Ah Hood Rd, Jln Rajah, Whampoa Rd, Jln Bahagia and Kim Keat Rd/Whampoa Dr.
		1998	31 May	Amended to Toa Payoh Temp Int.
		1999	TBC	Skips removed bus stops outside Rajah Maisonette along Jln Rajah and outside Tai Gin Apts and outside Moulmein CC along Ah Hood Rd.
			TBC	First bus from Toa Payoh Temp Int brought forward to 0530 hrs on weekdays.
		2000	TBC	Serves additional bus stop outside Blk 4 along Delta Rd.
Template:SBS Transit (Current)		2002	19 May	Amended to Toa Payoh Integrated Transport Hub.
		2003	21 June	Amended to ply Serangoon Rd, Boon Keng Rd and Bendemeer Rd under North East MRT Line Rationalisation Phase 1.
		2007	16 January	Skips relocated bus stop outside Dhoby Ghaut Stn along Penang Rd.
		2011	16 October	Amended to ply Middle Rd, Selegie Rd, Prinsep St and Bras Basah Rd with the partial closure of Bencoolen St to facilitate the construction of Bencoolen MRT station on the Downtown MRT Line.
		2013	3 December	Designated wheelchair-accessible bus service (WAB).
		2016	11 December	Amended to ply the reinstated Bencoolen St, skipping Middle Rd, Selegie Rd, Prinsep St and Bras Basah Rd.
		2018	28 October	Amended to ply McNair Rd and Towner Rd, skipping Serangoon Rd.

Short Trip 139A (2012 - 2014)

Operator	Year	Date	Service changes
Template:SBS Transit	2012	27 August	Introduced from Toa Payoh Int to Kim Keat Rd (Opp Jumbo Ind Bldg) during evening peak hours on weekdays.
	2013	3 December	Designated wheelchair-accessible bus service (WAB).
	2014	14 September	Discontinued with the introduction of Service 139M.

Short Trip 139A (since 2022)

Operator	Year	Date	Service changes
Template:SBS Transit	2022	12 December	Introduced from Toa Payoh Int to Jln Bahagia (Bet Blks 33/34) during evening peak hours on weekdays. Wheelchair-accessible at launch.

Service 139M (2014 - 2022)

Operator	Year	Date	Service changes
Template:SBS Transit	2014	14 September	Introduced between Toa Payoh Int and Jln Bahagia (Loop) under the LTA's Bus Service Enhancement Programme (BSEP). Wheelchair-accessible at launch.
	2022	11 December	Discontinued with the introduction of Short Trip 139A.

Service 140 (1971 - 1988)

Operator	Year	Date	Service changes
UBC	1971	11 April	Introduced between Lor 6 Toa Payoh Ter and Prince Edward Ter under 1971 Bus Reorganisation.
		2 August	Amended to Toa Payoh Town Ctr Ter.
	1974	24 February	Amended to ply Grange Rd, Orchard Blvd and Paterson Rd towards Toa Payoh Town Ctr Ter with the conversion of Orchard Rd to one-way traffic.
		8 December	Amended to ply Cecil St, skipping Robinson Rd.
	1975	21 July	Amended to ply Stamford Rd, skipping Coleman St and Armenian St.
	1976	14 March	Serves new staggered bus stop outside The Cenotaph along Connaught Dr, skipping the bus stop opposite Singapore Cricket Club.
	1979	11 February	Amended to ply the extended Shenton Way, Palmer Rd and Anson Rd, skipping Parsi Rd.
	1983	26 December	Amended to Toa Payoh Int, shortened to loop at Orchard Rd and converted into a semi-express service.
	1987	13 December	Serves new staggered bus stop outside Orchard Stn along Orchard Blvd, skipping the bus stop opposite Orchard Stn.
			Serves new bus stop outside Newton Stn along Scotts Rd.
	1988	24 January	Discontinued.

Service 140 (since 2014)

Operator	Year	Date	Service changes
Template:SBS Transit (Current)	2014	14 December	Introduced between Lor 1 Geylang Ter and St. Wilfred Rd (Loop) under the LTA's Bus Service Enhancement Programme (BSEP), operating between 0600 hrs and 2330 hrs daily.
	2015	30 March	Designated wheelchair-accessible bus service (WAB).

Service 140A (1971 - 1974)

Operator	Year	Date	Service changes
UBC	1971	11 April	Introduced between Lor 1 Toa Payoh Ter and Stamford Rd (Loop) under 1971 Bus Reorganisation.
		2 August	Amended to Toa Payoh Town Ctr Ter.
	1974	3 February	Re-numbered Service 136 under 1974 Bus Rationalisation.