The regiment arrived in South Africa in the beginning of December 1899, and joined General French in the Colesberg district. Along with the 6th (Inniskilling) Dragoons and 2nd Dragoons (Royal Scots Greys) they formed the 1st Cavalry Brigade, but the brigade did not actually operate together until the rush to Kimberley.
In the Colesberg district the regiment under Colonel Porter did most excellent work, as on 31st December 1899, and at Slingersfontein on 11th January 1900, and in his despatch of 2nd February 1900 General French made several appreciative references to their doings. Colonel Porter was very highly praised, and Major Garratt was also mentioned. As supplementing the despatch, the chapter in Mr Goldman's 'With General French and the Cavalry' is very valuable.
The cavalry about Colesberg, except two squadrons of the Inniskillings, went to Orange River and Modder River with General French in the beginning of February, preparatory to the movement on Kimberley. That march, and the subsequent operations on the way to Bloemfontein, has been touched on under the Household Cavalry. Colonel Porter was appointed brigadier general of the 1st Cavalry Brigade before the advance to Kimberley was commenced. On 16th February the brigade had heavy fighting on the northern outskirts of Kimberley. Early on the morning of 17th February Broadwood with his brigade left Kimberley to endeavour to head off Cronje at Koodoesrand Drift, and General French followed an hour or two later, two squadrons of the Carabiniers accompanying him.
The value of the services of the cavalry between 11th February and 13th March was recognised by Lord Roberts in his despatches, and the work of the 1st Brigade on the night of 12th March in seizing very strong positions commanding Bloemfontein was specially touched on.
In the despatch of 31st March 1900 Brigadier General Porter and 2 other officers and 6 non-commissioned officers and men of the Carabiniers were mentioned by Lord Roberts for good work up to the occupation of Bloemfontein.
On 29th March the 1st and 3rd Cavalry Brigades and the 12th Lancers took part in the action of Karee Siding. There, as usual, their outflanking movement on the left assisted in compelling the enemy to forsake his kopjes, but he succeeded in getting away all his guns and waggons. Hardly had the cavalry returned to Bloemfontein ere they were hurried out towards the Waterworks, in consequence of the disaster to Broadwood on the 31st March (see Household Cavalry). The relief sent was too late to be of any value, except that Porter's people brought in many of our wounded who had been taken prisoners, and who had been left by the Boers.
Lord Roberts commenced his northward movement on 3rd May, and on the 8th, French, with the 1st (Porter's), 3rd (Gordon's), and 4th (Dickson's) Cavalry Brigades, joined the Commander-in-Chief. The 1st and 4th with Button's Mounted Infantry were throw out on the left flank and had several times hard fighting, particularly on 10th May. The 3rd Brigade accompanied and fought in front of the centre. On the Queen's Birthday, 24th May, the Vaal was crossed by French's force, two days in front of the main army. On the 27th to 29th there was much fighting, which ended in the battle of Florida or Doornkop (see 1st Gordon Highlanders). On 4th June Porter brigade had again sharp fighting at Kalkheuve Keeping out to the left, French's force circled round Pretoria, which surrendered on the 5th, and at day-break on the 6th Porter was able to release over 3000 prisoners near Waterval. The 1st and 4th Brigades now took up positions north and north-east of the capital. At Diamond Hill, 11th and 12th June (see 1st Royal Sussex Regiment), they were heavily engaged on the extreme left, but the country was so difficult that the enemy's position could not be outflanked. It must be kept in mind also that the loss of horses had been such that the brigades were not at half strength.
Before the eastern advance commenced the 1st and 4th Brigades had much fighting north, north-west and north-east of Pretoria. In that advance, the first Brigade being now under Brigadier General Gordon, the services of both brigades were invaluable. After the battle of Bergendal, 27th August (see 2nd Rifle Brigade), French made a sweep first north, then south of the railway line, coming into and seizing Barberton from the direction whence he was least expected. The natural difficulties of this march were perhaps the most formidable troops with transport have met with in modern wars. A naval gun accompanied the force, and was hauled over the stupendous mountains by the roughest possible tracks. Barberton was reached on 13th September, and here again more prisoners were released, and a great depot of stores captured.
French was next ordered to take his force — the 1st Cavalry Brigade, Mahon's brigade, consisting of the 8th and 14th Hussars, with M Battery RHA, Dickson's brigade, now the 7th Dragoon Guards, Imperial Light Horse, and a horse artillery battery, with one half of the Suffolks — across the Eastern Transvaal to the Natal Railway. Leaving Machadodorp on the 12th and 13th October, the force entered Heidelberg on the 26th after much fighting. Early on the 14th the Carabiniers had captured a convoy and some prisoners, and much stock was taken. The regiment was frequently heavily engaged on this march, and lost Lieutenant Calvert and about 8 men killed, and 3 officers and about 12 men wounded.
Eight officers and 6 non-commissioned officers and men of the Carabiniers were mentioned in Lord Roberts' despatch of 4th September 1901.
In the second phase of the war, after Lord Roberts left South Africa, the movements of the cavalry are difficult to follow. The 1st Brigade were for a time west of Pretoria, and in January 1901 had fighting at Naauwpoort and other places. Thereafter the 6th Dragoon Guards and 2nd Dragoons under Colonel Allenby trekked to the east of the Transvaal via Bethel, Amsterdam, and Piet Retief, when General French was carrying out his big sweeping movement in February, March, and April 1901, in which operation enormous quantities of stock and stores and practically all the enemy's artillery in that part of the country were captured.
During May, June, and July 1901 these two regiments operated under Colonel Allenby in the valley of the Vaal River, about the head waters of the Wilge River, and thereafter in the Western Transvaal. In September 1901 another sweep under General Plumer was made to the eastmost corners of the Transvaal, thence up to the high veldt about Standerton, where Allenby's column was when the news of Benson's disaster on 30th October came to hand. The column, strengthened by some Australians and the 18th and 19th Hussars, set out after the Boers, and after much chasing inflicted a good deal of loss; and so on to the end of the war, everlastingly pursuing and watching for traps. Few regiments during the last year of the campaign pursued with more fruitful result or more successfully avoided the traps.
During the later phases of the war the Carabiniers had 1 officer and 9 non-commissioned officers and men mentioned by Lord Kitchener in despatches, and in the final despatch the names of 4 officers and 5 non-commissioned officers and men were added. The regiment had produced Brigadier General Porter and several most successful column leaders, notably Majors Garratt and Leader.