Early in March 1823, the commanding officer, Lieutenant-Colonel Thornton received an intimation that it was intended to send the regiment to New South Wales. In the meantime it was ordered to proceed to Dublin, thence by sea to Liverpool, and after that by road to Chatham, in order to form guards for convict ships when required.
The head quarters reached Dublin on 15th March and occupied the Royal Barracks. On the 30th the whole regiment embarked at Pigeon House, in eight small vessels, and reached Liverpool the following day.
A twenty eight days' march, including three Sundays, brought the regiment to Chatham. The Regiment marched in three divisions; the first arrived at Chatham on 21st April; the second, consisting of two companies, halted, and remained at Deptford; and the 3rd reached Chatham on 23rd April.
During the next year the 40th was sent out, in small detachments, as guards on board convict ships to Australia. This was after several years' rough service in Ireland, and but a short period of rest in England........
Embarked; 25th April 1823 on ship Albion. Lieutenant Lowe
Embarked; 5th July 1823 on ship Asia Captain Bishop
Embarked 10th July 1823 on ship Isabella. Lieutenant Millar
Embarked 18th July 1823 on ship Sir Godfrey Wilestoe. Captain Hibbert
Embarked 29 July 1823 on ship Guildford. Captain Thornhill
Embarked 31st July 1823 on ship Medina. Lieutenant Ganning
Embarked 5 August 1823 on ship Castle Forbes. Lt.- Col. Balfour
Embarked 29 December 1823 on ship Prince Regent. Captain Stewart
Embarked 5th February 1824 on ship Chapman. Captain Jebb
Embarked 25 February 1824 on ship Countess of Harcourt. Captain Morow
Embarked 14 June 1824 on ship Mangles. Lt.- Col Thornton
Embarked 14 June 1824 on ship Princess Charlotte. Lieut Neilley
In August 1823 Jackson's Oxford Journal reported -
On Thursday, 160 convicts were transhipped from the Hulks at Portsmouth for the Guildford bound to New South Wales, and placed under the superintendence of Mr. J. Mitchell, Surgeon, R.N. The rapid increase of emancipated convicts, the last returns being 7556 and 5859 children has determined Government to establish a Court of Judicature in the colony. Chief Justice Sir Francis Forbes and family go out in the Guildford. As well as Chief Justice Forbes, Lady Amelia Sophia Forbes and their three children, passengers included Mr. James Glennie.
Two sons of surgeon John Dulhunty, Robert Venour Dulhunty and Lawrence Vance Dulhunty also came passengers.
Lady Amelia Sophia Forbes kept a brief diary on the voyage. 
Sir Francis Forbes
The Guildford arrived at Portsmouth from the Downs on 13th August and departed Portsmouth on 18 August 1823 in company with the Asia which was taking convicts to Van Diemen's Land.
Rio de Janeiro
The Guildford sprang a leak after leaving Teneriffe and was compelled to put into Rio for repairs. Probably she was fortunate to make the south American port, as the leak necessitated continuous pumping. She was hove down and rendered watertight, the guard and convicts being transferred to a hulk lent for the purpose by the Brazilian government. Her two months' sojourn at Rio caused considerable sickness among the convicts but the only man to die on the passage was accidentally killed when, in the high southern latitudes, he was flung into the hold and pitched on his head. The Guildford did not leaving there until December 1823. (3) Select Movement of the 40th regiment to find out more about the voyage.
When the Guildford arrived in Sydney on 5 March 1824 with 159 male prisoners, the Sydney Gazette reported:
Arrived on Friday last to the joy of the whole Colony, alarming apprehensions being entertained of her safety, the ship Guildford, Captain Johnson, from England. She brings 159 male convicts: the original complement was 160, but one was accidentally killed.
The prisoners were landed on 8th March 1824. Fifty-seven men were forwarded by water to Parramatta for distribution to Liverpool, Airds, Appin, Minto, Windsor and Bathurst. The following day another thirty one men were sent to Parramatta, twenty-four to Liverpool, sixteen to Bathurst and five to Windsor.
Departure from the Colony
The Guildford departed Sydney for England via Hobart in June with invalids from the 48th regiment on board viz 3 serjeants and 28 privates with 7 women and 14 children under the charge of Lieutenant Croasdaile of the Buffs.
Notes and Links
1). James Mitchell was also surgeon on the convict ships Neptune in 1820 and Guildford in 1822
6). Return of Convicts of the Guildford assigned between 1st January 1832 and 31st March 1832 (Sydney Gazette 14 June 1832; 21 June 1832)
Isaac Eaton - Ploughman assigned to George Bunn in Sydney; and Thomas Bray at Concord William Hague - Blacksmith assigned to John Pike at Hunter's River
 Sydney Gazette 11 March 1824
 Bateson, Charles Library of Australian History (1983). The convict ships, 1787-1868 (Australian ed). Library of Australian History, Sydney : pp.344-345, 384