The Indian Trooping season generally began with troop ships leaving England in September, and ended with the last ships leaving India in March. This pattern was probably established once troop ships no longer sailed around the Cape of Good Hope and started using the "Overland Route", and then the Suez Canal after its opening in 1869.
The reasons for a restricted period were to travel in the cooler months so that
- troops were not travelling during the hot summer months in unventilated ships, particularly in the Red Sea and the Gulf of Aden, when conditions could become dangerous.
- unacclimatised troops from Britain were not travelling from the ports of Bombay or Karachi to their cantonments during the heat of an Indian summer.
- In 1916, when normal procedures were disrupted due to the First World War, the "Karachi troop train incident" of the 5th June, 1916, resulted in the death of nineteen Territorial Troops due to heat stroke on a troop train between Karachi and Lahore.
Initially troops changed ships at Suez, so there were different ships on the routes England to Suez, and Suez to India, but subsequently (and by 1886) ships sailed a round trip from England to India, approximately three weeks in each direction.
Each season generally there were only two of the twelve or so voyages which called at Aden on the way out to India and three on the way back. The extra one coming from India was needed to effect the annual relief of the British infantry battalion in Aden.
HM Indian Troopships
Although generally referred to as HM Indian Troopships, the official designation was HMS Her Majesty's Ship. The Euphrates- class troopships were a group of five purpose-built troopships paid for by the Indian Government and launched in 1866-7. The sister-ships were the 'Crocodile', 'Euphrates', 'Jumna, 'Malabar' and 'Serapis'. Each ship could transport a full battalion of infantry with its married families, or about 1,200 people.
Before the opening of the Suez Canal the 'Crocodile' and 'Serapis' ran between England and Alexandria, whilst the other three ran from Suez to Bombay.
By 1894, four of the five naval troopers were laid up while two P&O ships, 'Victoria' and 'Britannia' had a trial as troopers on charter. The two newcomers soon demonstrated that they could make a better job of it than the old naval ships and 'Crocodile' and her sisters were disposed of in 1896
The ships were then designated HMT Hired Military Transport. During the First World War HMT could also mean His Majesty's Transport, but this use was probably unofficial, as the terminology would officially only apply to commissioned ships.
Movements of Crocodile 1886-1888
- 6th Oct Sailed Portsmouth for Bombay;
- 2nd Nov Arrived Bombay
- 13th Nov Sailed Bombay for Portsmouth via Suez
- 8th Dec Arrived Portsmouth
- 22nd Dec Sailed Portsmouth for Egypt
- 8th Jan Sailed Suez for Bombay;
- 14th Feb Sailed Bombay for Portsmouth;
- 11th Mar Arrived Portsmouth
- 17th Mar Capt. Richard Evans assumed Command. End of trooping season.
- 7th Sep Sailed Portsmouth for Bombay via Queenstown. Commencement of trooping season.
- 5th Oct Arrived Bombay
- 15th Oct Sailed Bombay;
- 10th Nov Arrived Portsmouth
- 23rd Nov Sailed Portsmouth for Bombay;
- 20th Dec Arrived Bombay
- 31st Dec Sailed Bombay
- 25th Jan Arrived Portsmouth
- 08th Feb Sailed Portsmouth for Bombay via Plymouth;
- 7th Mar Arrived Bombay
- 17th Mar Sailed Bombay
- 12th Apr Arrived Portsmouth
- 7th Sep Sailed Portsmouth for Bombay
1904-05 Trooping Season
"The Indian Trooping season will begin in September… The following are approximately the dates on which the ships will start from Southampton and arrive there on their return.
- 1. September 8-November 3
- 2. September 30-November 12
- 3. October 1-November 24
- 4. October 11-December 8
- 5. November 15-January 6, 1905
- 6. November 23-January 18, 1905
- 7. December 6-January 28, 1905
- 8. December 17-February 8, 1905
- 9. January 17, 1905-March 11
- 10. January 28, 1905-March 28
- 11. February 7, 1905- April 5
- 12. February 18, 1905-April 13" 
- "Troopships and Trooping" Transcript of an article from Shipping Wonders of the World, part 39, published 3 November 1936.
- Troopships and Trooping by R G Robertson movcon.org.uk, now archived, archive.is. Includes mention of troopships to India. Archive.org link.
- Bad conditions on troop ships coming to India in the late 1700s are mentioned in "The soldier's friend—Sir Jeremiah Fitzpatrick" by Richard L. Blanco Med Hist. 1976 October; 20(4): 402–421, particularly 415-417
- First page only, "A Soldier's Life in Burma and India 1854-1874" by W. G. Shelton, Journal of the Society for Army Historical Research Vol. 52, No. 209 (Spring 1974), pp. 17-33. Based on a memoir by Sergeant-Major Alexander Morton of the 35th Regiment of Foot. Contains a description of the conditions on board the ship to India.
- "Transport of Troops to India" by Frederick Engels from New York Daily Tribune, 13 August, 1858 states that some troops were sent from England by the overland route from 1857. Marxists.org. This route became permanent some years later, see Historical books online, below.
- Terrible conditions are described in a Letter home from a soldier’s wife on a voyage to India 1859 As a result, the Captain was murdered!
- Eastern Monarch 1859 Fire broke out in English waters on this ship, whose passengers included 352 invalid soldiers from North West India. Old-merseytimes.co.uk.
- *The Diary of Job Shepherd Waterhouse, 1864 – 1870 Pte. 19th Foot Regiment No.1691. There are descriptions of the voyage to India in 1865 on the Malabar, and the return to England in 1870, on the Euphrates. greenhowards.org.uk, now an archived webpage.
- Troopship movements: The Crocodile 1878-1881 during the 2nd Afghan War. garenewing.co.uk
- The Indian Relief Trooping Season, passing through the Suez Canal Illustration for The Graphic, 12 September 1891.
- Indian Troopships Hansard 01 January 1894. Crocodile is about to be paid off after a serious breakdown near Aden. Serapis and Euphrates shall be withdrawn from service at the end of the present season.
- Image: HM Transport "Rewa" No.4 Mail List (Trooping Season 1909-1910). The "Rewa" travelled Southampton to Karachi, and return. University of Limerick WW1 Online Exhibition
- Voyage to India: Memoirs of the 1st/3rd Kent Battery 1914 Frank William Critchley was 22 years old and a sergeant in the 1st/3rd Kent Battery, Royal Artillery. He travelled to India on the troopship Grantully Castle which departed Southampton 29 Oct 1914 and arrived Bombay 2 December 1914. voyagetoindia.co.uk
- A letter written by Harry Beaumont, 1/6 East Surrey Regiment, No. 2297, from a collection of letters written by staff at the Audit office for the Great Western Railway (GWR) based at Paddington, London. The National Archives.
- Troop ship: ‘five weeks on board’ 29 November 1914, written onboard SS Grantully Castle.
- An Excerpt from the Diaries of Private John Charles Waters February- March, 1916, now an archived webpage. He was a member of the 1st/1st Kent Cyclists and travelled on the S.S."Benalla" a Peninsular and Oriental liner, to Kebbal Camp, Bangalore.
- Life on a Troopship A Pictorial History featuring the photographs of John Ernest Brown Royal Sussex Regiment. warlinks.com. He sailed to India in 1932, and returned in 1937, via Egypt (1935) and the Sudan (1936)
- "Every Day A Bonus" by Ken Clarke from Regimental Association of The Queen's Own Buffs (PWRR): The Journal issues No 11-14 Autumn 2005- Spring 2007. The pages covering the voyage to India in 1933, time in India, and voyage back to England in 1938 are (11)48-49; (12)29-39; (13)15-25; (14)38.
- Issue 11, 12, 13, 14 thequeensownbuffs.com
- Issues 11 and 14. He joined the Army as a Boy Musician in 1932 aged 14 and went as part of a a draft to India leaving 4th February 1933 on the troopship HMT Dorsetshire, returning to England on the Dilwara arriving Southampton on 13th January 1938.
- The King's Shilling — Part 2a – India by Neil Walker. bbc.co.uk/ww2peopleswar. Contains a mention of the Trooping season c 1937
- Troopship to Bombay  from the 1944 diary of Sidney Greaves. He was a radar operator for the RAF. bbc.co.uk/ww2peopleswar.
- "Voyage to India (1945)" by Des McDougall. Part 1, Part 2, Part 3, Final Stage He was a British Officer Cadet, who travelled on the S.S. Otranto, whose destination was the Officers’ Training School, Bangalore. bbc.co.uk/ww2peopleswar.
- "Death Of Territorials In India". House of Lords. Hansard 25 July 1916 vol 22 cc911-6, 01 August 1916 vol 22 cc1037-42. "Karachi Troop Train Incident". House of Lords. Hansard 18 May 1920 vol 40 cc390-404, 21 July 1920 vol 41 cc413-20. 10 August 1920 vol 41 cc1169-79
- 'Perceptions of, and reactions to, environmental heat: a brief note on issues of concern in relation to occupational health" by Delia Rizpah Hollowell Global Health Action December 29, 2010. (scroll down) Includes the statement “In 1884 Major-General MacGregor, Quarter Master General in India, wrote of the ‘risk incurred by the prolongation of the trooping season so far into the hot weather,’ arguing that the last British vessel should leave India no later than the 1st of April (14)". Footnote 14 states "14. MacGregor CM. Letter from Major-General Sir CM MacGregor, K.C.B., C.S.I., C.I.E., Quarter Master of India to the Secretary to the Government of India, Military (Marine) Department No. 3515-A. 1884 Indian troop service: general arrangements 1884–85. The British Library File No. 12861 IOR:L/MIL/7/10235".
- Euphrates-class troopship Wikipedia
- Photograph: HMS Malabar c 1870 flickr.com
- The Last of the Indian Troopships, HM Indian Troopship Malabar, painting 1881. nam.ac.uk
- Troopships - HMT Malabar the last of the Indian Troopships kingsownmuseum
- HMS Serapis nelsonlambert.com
- The Indian Troopships "Clive" and "Tenasserim" in Madras Harbour c 1885. Click to enlarge. British Library Online Gallery
- Arrival of the "Tenasserim" at Rangoon on 8th Nov, 1885 Click to enlarge. British Library Online Gallery
- Troopships and the Regiment. 1, 2, 3 queensroyalsurreys.org.uk
- Postcard: Palitana troopship leaving Bombay Wikimedia Commons. Palitana sailed from Bombay on 23rd September 1899 carrying 2nd Bttn. Gordon Highlanders and this is probably that departure.
- BI Troopships 1902 to 1922, BI Troopships from 1923, now archived. merchantnavyofficers.com
- HM Troopship Plassy. Sailed 1901 until scrapped in 1924, including the Indian Garrison rotation run. During the First World War she was converted for use as a hospital ship. roll-of-honour.com
- HMT Dongola. Used for seasonal trooping from 1906 between England, India and Hong Kong. King's Own Royal Regiment Museum. Dongola 1905-1926 simplonpc.co.uk
- H.M.H.S. Grantually [sic] Castle Prior to becoming a Hospital Ship during WW1, the Grantully Castle was used as a troopship, including a trip to India at the end of 1914, refer above.
- Image: HMT Hecuba photoship.co.uk, now archived. Originally the "Brandenburg", built in 1901 for Norddeutscher Lloyd. The ship was awarded to Great Britain as war reparation in 1919 and had brief service as a troopship 1922-1924. There was a voyage from Southampton to Bombay, arriving 1 December 1924.
- HMT Neuralia - Troop Ship the-weatherings.co.uk. Neuralia, built 1912, operated as a permanent troopship from 1925. The book Pick up your Parrots and Monkeys by William Pennington, see History reading list, contains a chapter on the voyage to India on the Neuralia in the 1930s.
- Photograph: HMT Nevasa - Troopship Nevasa, built 1913, operated as a troop ship from 1925
- MS Dilwara and her three sisters, MS Dunera, Ettrick and Devonshire ssmaritime.com. MS Dilwara and Dunera were completed in 1936 and 1937, and the second pair MS Ettrick and Devonshire in 1938
- Photograph: August 17, 1947, soldiers from The Royal Norfolk Regiment embark on the S.S. Georgic bound for Britain on the quayside in Mumbai, the first British Army unit to leave Indian soil after the country achieved independence. mid-day.com. Video: British Troops Leave India 1947 British Pathe on YouTube . This video appears to be of the same troops as in the photograph although they are unnamed. They are however sailing on the 'Georgic'.
- Photograph: Troopship HMS Otranto. Voyage home from India to UK in 1947, from the collection of James Wilson, Royal Artillery
Historical books online
- "East India (Transport of Troops"). Report of Select Committee c 1858 page 308 'Series F British India, Colonies etc' Annals of British Legislation, Volume 5 edited by Leone Levi 1859 Google Books
- "Report on the Ships "Clifton Belle" and "Dudbrook," which arrived at Kurrachee with Soldiers' Families in March 1860" by Surgeon Major D.Grierson M.D., Staff Surgeon, Kurrachee. Appendix page l, Transactions of the Medical and Physical Society of Bombay, Volume VI, New Series 1860 Google Books. There were many deaths on board, particularly of young children
- Conveyance to India of soldiers’ wives and families: Mortality statistics on the voyage, for 1859-60 Page 14 onwards and Page 74 [Parliamentary Papers] Reports from Commissioners: [including] Emigration Session: 5 February-6 August 1861. Google Books
- "The New Overland Troop Service to India" Colburns’s United Service Magazine 1867 Part 3, page 226. Google Books. (The Suez Canal was subsequently opened for navigation on 17 November 1869)
- Periods for embarkation page 239 The Queen's Regulations and Orders for the Army 1868 Google Books
- 24 coloured views of H.M. Indian troop-ship to Bombay & back, published 1885. Bodleian Library Oxford Digital version. Possibly "Jumna". Catalogue entry with link, direct pdf (may be slow to load)
- A voyage to India on the Malabar in 1889 page 47, Some Rambles of a Sapper by Brigr-Genl. Herbert Henry Austin. 1928 Hathi Trust Digital Library
- "The Peregrinations of an Officer’s Wife" page 178 Blackwood’s Magazine, no 211 January-June 1922 Archive.org. Includes description of voyages to, and from, India.
- Seven Cantonments by Major SEG Ponder c 1938. The author was an Officer in the Royal Artillery. He describes the voyage to India on HMT Devon in the c 1930s from page 21. Archive.org, Digital Library of India Collection.
- "Hot weather precautions" Volume II , Part I - Annual report on the health of the army in India for the year 1939, page 107 National Library of Scotland “ Medical History of British India”
- Troopships from "Aden in Days of Empire". peterpickering.com/aden, now archived
- Preece, Nigel HM Indian Troopship Crocodile Rootsweb India Mailing List 28 January 2000. Retrieved 18 January 2019.
- qprdave HMS Crocodile World Naval Ships Forum 9 January 2011. Retrieved 26 February 2015
- "Chaplains for Troopships" page 15 The Tablet, 20th August 1904
- dunnboer Numbers for transport ships? angloboerwar.com.
- Ebay, seller three4five
- "A Few Stations In India" by Mrs. H. V. Bagshawe. Journal of the Royal Army Medical Corps 1926;46:3 214-223.
- A History of the British India Steam Navigation Company Limited , pages 17 and 62. Pdf rakaia.co.uk.
- A History of the British India Steam Navigation Company Limited, page 62.