The regiment sailed on the Armenian on 8th February 1900, and arrived at the Cape on 1st March. Along with the 8th and 14th Hussars they formed the 4th Cavalry Brigade under Brigadier General Dickson. The 3rd and 4th Brigades took part in the movement to the south-east of Bloemfontein, commencing about 21st April, with the object of clearing the way to Wepener, then besieged. That place having been relieved on 24th April, the cavalry under French marched to Thabanchu to clear that stronghold preparatory to Ian Hamilton beginning his march north (see Duke of Cornwall's Light Infantry). The 4th Brigade were on the left in the action at Thabanchu, and had rather a hard task. An excellent account of the engagement is given in Mr Churchill's 'Ian Hamilton's March'. On 1st May there was further fighting at Hout Nek, in which the 8th Hussars had heavy work and did it well.
Both brigades rejoined the main army on 8th May, and the 4th were along with the 1st on the extreme left on the way to Pretoria (see 6th Dragoon Guards). At Diamond Hill, 11th and 12th June (see 1st Royal Sussex Regiment), both brigades were again on the left, and found that the task of turning the enemy's right was beyond their strength, then at a very low ebb, while the country was all against an outflanking movement.
In the beginning of July 1900 the regiment was holding Waterval post, north of Pretoria. On the 11th they were heavily attacked, and as stated by Lord Roberts in his despatch of 10th October 1900, para 20, "the 7th Dragoon Guards were well handled, and our loss would have been trifling had not one troop mistaken the Boers for their own comrades". The regiment lost 1 officer and 3 men killed, 2 officers and several men wounded.
The 4th Brigade took part in the eastern advance, and accompanied General French to Barberton, and thereafter to Heidelberg (see 6th Dragoon Guards). The brigade remained for a time about Heidelberg, and after Clements' disaster at Nooitgedacht was taken to Krugersdorp to assist in clearing the Megaliesberg. Later in December the 7th Dragoon Guards were brought to Cape Colony to help in driving out the invaders.
In Lord Roberts' despatch of 4th September 1901 9 officers and 6 non-commissioned officers and men of the regiment were mentioned for good work up to the time of his lordship leaving South Africa.
Having been brought north again to the Orange River Colony, the regiment was in March 1901 brigaded with three Yeomanry battalions under Major General Broadwood, and took part in very numerous movements during the ensuing months, under the direction of General Elliot, in the north-east of that colony. The regiment was employed in that district for practically the remainder of the campaign. The work there was absolutely incessant, going on often night and day. In his despatch of 8th August 1901, para 4, Lord Kitchener says, "At midnight on 30th July Colonel Lowe, 7th Dragoon Guards, successfully surprised a farmhouse, from which he took 11 armed prisoners, with rifles, bandoliers, and horses". It was these useful captures and constant night attacks which were to worry the enemy into ending the campaign. In Lord Kitchener's despatch of 1st June 1902, describing one of General Elliot's final sweeps, he says, "Farther to the south an endeavour to penetrate General Elliot's screen near Deilfontein was promptly and gallantly repulsed by the 7th Dragoon Guards, who drove back the Burghers with a loss of 4 men and 28 horses killed, and 5 men and 16 horses captured".
Two officers and 5 men gained mention in Lord Kitchener's despatches during the campaign, and in the supplementary or final despatch 4 officers and 4 non-commissioned officers were mentioned.