Sailed on the Zibenghla before war was declared, and had anything but a prosperous voyage, the machinery breaking down frequently and the water running short. Along with the 75th was the only artillery Lord Methuen had in the actions of Belmont, 23rd November 1899 (see 3rd Grenadiers), and Enslin, 25th November, and up till late in the afternoon these were the only batteries at Modder River, 28th November. At Belmont the artillery horses, not yet hardened up, were utterly unable to pursue at the close of the day—"dead-beat", Lord Methuen said. At Enslin it was much the same, but the artillery did very good work both before and during the action. At Modder River they were invaluable. In his despatch of 1st December 1899 Lord Methuen said: "During the entire action the 75th and 18th Batteries had vied with one another in showing gallantry and proficiency. I dare not write more than Colonel Hall has written, his modest account scarcely doing justice to the splendid conduct of our gunners. The 62nd Battery, marching from Belmont, came straight into action and were of great service". The 18th, 62nd, and 75th did excellent work at Magersfontein. Major General Marshall told the War Commission that the rounds expended were—by the 18th, 1012; the 62nd, 1003; and by the 75th, 924. In the eastern advance these batteries were attached to Tucker's division, and at Paardeberg fired hard from the south bank.
At Karee Siding, 29th March 1900 (see 2nd Norfolk), these three batteries were the field artillery present. They accompanied Tucker's division in the advance to Pretoria, and were present in numerous other engagements. From June 1900 to March 1901 the 18th Battery had its headquarters at Pretoria, sections being frequently detached on outpost duty in that vicinity and about Pienaar's River. In March 1901 the battery, along with a section of "pom-poms", formed the artillery of General Plumer's column in his advance to Pietersburg. Two guns remained at Pietersburg till the battery left South Africa, the remaining four guns operating under General Plumer in the Transvaal, the Orange River Colony, and on the Natal border. The 18th Battery represented the Field Artillery at the ceremony of proclaiming the annexation in Pretoria on 25th October 1900. The battery sailed for India before the close of 1901.