On their arrival at Bloemfontein, the 2nd contingent was attached to General Pole-Carew's Xlth Division, with which they served from 1st May to the end of October 1900, with the exception of a period of a few weeks about the end of June and beginning of July, when they were detached to assist on the lines of communication in the Orange River Colony. The 2nd contingent were engaged at Brandfort, 3rd May; Vet River, 4th May; Zand River, 9th and 10th May; at the Vaal, 26th May; outside Johannesburg on the 28th, 29th, and 30th; at Six-Mile Spruit on 4th June; Silverton, 8th June; Diamond Hill, 11th and 12th June.
At the crossing of the Vet River about 30 of the 2nd contingent seized a kopje of much importance, and, although far from support, held on till next morning. Lord Roberts congratulated them on this piece of good service. In his telegram of 7th May he gave the West Australians the credit of discovering explosives on the railway and thus saving accidents. Again, in his wire of 28th May from Klip River, Lord Roberts said: "The enemy had prepared several positions where they intended to oppose us, but they abandoned one after another as we neared them. We pressed them so hard that they only just had time to get their five guns into the train and leave this station as some of the West Australian Mounted Infantry entered it". A party were also said to have gained credit by holding a drift, shortly before the surrender of Johannesburg, for eight hours against a very superior force of the enemy. Lieutenant L D H Potter was wounded on 30th May.
Both the 1st and 2nd contingents were heavily engaged at Diamond Hill.
The 2nd contingent took part, under Pole-Carew, in the advance from Pretoria to Komati Poort, starting about 23rd July. They had fighting in the Belfast district on 28th August and frequently thereafter. In his telegram of 13th September Lord Roberts remarked that the West Australians had been scouting in front of Pole-Carew's Division. At Waterval Onder, on 3rd September, Lieutenant Darling and 8 men were wounded. The West Australians were said to have been the first to discover much railway material and other valuable stores near the Poort. They were present at the big review held there on 28th September. After their stay in that unhealthy neighbourhood, they were employed about Machododorp, where they suffered some casualties throughout October.
In January and February 1901 the 2nd contingent was employed in Cape Colony, and assisted to drive out the invaders. At Klipplaat, on 5th February, Captain Olliver and several men were wounded. Captain Olliver had been sent in command of a small force, 12 men of the 7th Dragoon Guards, 12 West Australians, and 3 Cape Police, carrying despatches from Colonel Haig to another leader. The little body was surrounded by several hundreds of the enemy. They kept up a good fight from 11 am till sundown, but were eventually all overpowered. Four of the Dragoons were killed and several were wounded.
On 31st March 1901 the last of the 2nd contingent, under Lieutenant Duffy, sailed for Australia.