The 1st contingent, 130 all ranks, with two maxims, sailed on the Medic from Albany on 5th November 1899, and arrived at Cape Town on the 26th of the same month. On their arrival in South Africa they were, along with the remainder of the Australian Regiment of infantry, employed on the lines of communication between De Aar and Modder River (see 1st Victorian Contingent). In January 1900 they were converted into mounted infantry, and were about the beginning of February sent to join the forces under General Clements in the Colesberg district; and the good work which they did there was frequently mentioned by correspondents and other writers on the war. On 6th February the West Australians were under fire for the first time, and had their first casualty. A reconnaissance in difficult country being necessary, 80 Westralians under Major Moor, an officer of the Royal Artillery, commanding the contingent, and Lieutenant Parker, formed part of a force sent out towards Potfontein. Moor's men came under a very heavy fire, but only one man was wounded. Major Moor himself narrowly escaped capture. He had given his horse to a dismounted Lancer, and was endeavouring to catch another horse: while doing so he was close to a party of Boers ensconced among rocks which some Lancers had just vacated. His subaltern noticed the peril of his senior, and galloping up took him up behind, and both got away. On the 9th Moor and 20 of his squadron were ordered to hold a kopje, which was placed as inside the heels of a horse-shoe. The Boers occupied the whole of the hills forming the shoe itself, and brought a very heavy fire to bear on Moor's position, but he held on till ordered to retire. Sergeant Hensman was mortally wounded, and Private Con way was killed while tending his non-commissioned officer. Six other men were wounded. Major Reay, in his 'With the Australian Regiment1, gives a detailed account of the engagement. He mentions that Private Kruger built a sangar round Hensman under a very heavy fire: his helmet was pierced by one bullet, his bandolier torn by another, while a third skinned his knuckles. Other non-commissioned officers and men distinguished themselves by running with messages across a bullet-swept zone. General Clements was very highly pleased with the conduct of the West Australians, and published the following order: "Operations at Slingersfontein, 9th February 1900.—The General Officer Commanding wishes to place on record his high appreciation of the courage and determination shown by a party of 20 men of the West Australians under Captain Moor in the above operations. By their determined stand against 300 or 400 men they entirely frustrated the enemy's attempt to turn the flank of the position".
In the fighting between the 10th and 13th February the West Australians were on the right of the line, near the Worcestershire Regiment, along with whom they took an honourable share in the very severe engagement on the 12th, when the Boers attacked Clements' positions, particularly on the two flanks (see Victorian Mounted Rifles), with the very greatest determination and in great strength. As has already been stated under the Victorian Contingents, the Boers did not renew their attack on the 13th, but General Clements decided that, in view of the overwhelming numbers of the enemy, it would be well to retire from the positions in front of Rensburg to Arundel. During this movement, which commenced about midnight 13th-14th, Major Moor's West Australians formed the left flank guard. During the next fortnight the outpost duty was very severe: the Boers being in great strength, Clements had to exercise every possible precaution. On the 20th the enemy renewed his attack, but the British were able to hold all their positions till fighting ceased. On this occasion the West Australians had been holding advanced outposts during the preceding night, and when the engagement commenced they could neither be fed, relieved, nor reinforced. Their position being well prepared they held it without loss, and claimed to have inflicted many casualties on their assailants. On the 22nd, 23rd, and 24th there was more fighting—General Clements making a bold but unsuccessful effort to drive back the enemy. A composite company of West and South Australians, officered by Major Moor, Lieutenants Darling and Campbell, West Australians, and Stapleton, South Australians, did good work, and got so far forward that they had difficulty in getting back. On the 27th it was found that the Boer leaders were withdrawing towards the Orange River. On the 28th Colesberg was occupied. On the 4th of March the West Australians, along with the 1st Victorian Contingent, were in a sharp engagement, in which they drove back the enemy, who left 8 dead.
Captain Forrest, in an excellent record of the work done by the Mounted Infantry Company of his battalion, published in the 'Oxfordshire Light Infantry in South Africa', says, under date 27th February, "The company was attached to a force, under Major King-King, ordered to guard the right flank of the advance" (from Colesberg to Norvals Pont on the Orange River). "The force consisted, besides ourselves, of one section 'J' Battery, RHA, one company West Australians, and two companies Prince Alfred's Guards. The West Australians, under Major Moor, were a splendid body of men. They compared more than favourably with any other Colonials met with afterwards. When the column arrived at the Orange River, it was found that the three centre arches of the bridge had been destroyed by dynamite. The Boer position on the north bank having been shelled, volunteers who could row were then asked for, and the West Australians were able to send in, among others, the name of the champion sculler of Australia".
In the advance to Bloemfontein the West Australians were attached to the right column of General Clements' force. This column consisted of a squadron Inniskilling Dragoons, some guns RFA, the Mounted Infantry of the Oxford Light Infantry and West Riding Regiments, and the West Australians.
In Lord Roberts' despatch of 15th March 1900 he mentioned that there was organised disaffection in the Prieska district, and that various columns were dealing with the rebels. Among the troops engaged was one company of West Australian Mounted Infantry. This was the 2nd contingent, commanded by Captain H L Pilkington, which had sailed from Freemantle on 3rd February. The rising was put down in March, but some West Australians continued to operate in the district during part of April. The 2nd contingent arrived at Bloemfontein in time to take part in the advance to Pretoria in May.
After their arrival at Bloemfontein the 1st West Australians were put into a Mounted Infantry Corps, commanded by Lieutenant Colonel De Lisle, and composed of themselves, the 6th Battalion Mounted Infantry (Regulars), and the New South Wales Mounted Infantry. This corps saw much fighting on the way to Pretoria.
Both the 1st and 2nd contingents were heavily engaged at Diamond Hill. They had some casualties. De Lisle's men were said by Lord Roberts to have done well. In his telegram of the 16th Lord Roberts said: "Botha's army has retired, believed to Middelburg. His rear-guard was surprised and thoroughly routed by Ian Hamilton's Mounted Infantry, chiefly West Australians and 6th Battalion".
On 16th July a detachment of the 2nd West Australians at Pienaar's Poort, on the left of General Pole-Carew's position, east of Pretoria, successfully repulsed a Boer attack.
In his telegram of June 28th and despatch of October 10th, para 15, Lord Roberts remarks: "On the 27th June the post on the railway near Roodeval Station was attacked, but the enemy was repulsed by a detachment of the Shropshire Light Infantry and the [1st] West Australian Mounted Infantry, with the aid of a 15-pounder gun on an armoured train".
Ridley's Mounted Infantry Brigade, including the 1st West Australians, formed part of the force which Sir Archibald Hunter led into the north-east of the Orange River Colony with the view of surrounding, if possible, the enemy under De Wet and Prinsloo in the Wittebergen or Brandwater Basin, as the district was more generally called. On the night of 15th July De Wet, with about 1600 men and some guns, escaped from Slabbert's Nek. Broadwood with the 2nd Cavalry Brigade and Ridley's Mounted Infantry were sent in pursuit. The Boers succeeded in reaching the railway and cutting the line. On 22nd July General Knox at Kroonstad wired to the General in Command at Cape Town as follows: "Following from General Broadwood, commanding 2nd Cavalry Brigade, sent by despatch rider to Honingspruit and wired from there to Kroonstad, begins—Have followed commando since July 16th, had sharp fight at Palmietfontein on July 19th. Prevented from pursuing laager by darkness: eight dead Boers found. Our casualties: killed, Major Moor, West Australian MI, and 4 men wounded, Lieutenant Stanley, 10th Hussars; Lieutenant Tooth, Australian Contingent, and 14 men". Major Moor's death was a heavy loss to the West Australians. His fine leadership had brought his corps into great prominence, when their small numbers are kept in mind. The West Australian losses at Palmietfontein, as afterwards announced, were, apart from Major Moor, 1 killed and 6 wounded. In the fighting at Stinkhoutboom on 24th July, the West Australians had 2 men killed and 3 severely wounded. After this De Wet took refuge in the Reitzburg hills on the south side of the Vaal, but about 7th August he crossed the river, evaded Lord Methuen's forces on the north bank, and made for the Northern Transvaal, crossing the Megaliesberg mountains by a pass which Lord Roberts had intended to have blocked, but from which the troops had been removed by an error. Lord Kitchener, with Broadwood's, Ridley's, and other columns, took up the pursuit, crossed the Vaal with all possible rapidity, and followed up at a great pace; but beyond releasing some 60 British prisoners and taking some waggons and one gun, the pursuit failed. Lord Kitchener was, however, able on 16th August to relieve Colonel Hore at Elands River (see Rhodesian Regiment). Mr Green, in his 'Story of the Australian Bushmen', mentions that the first troops to ride into Elands River and receive the heartfelt thanks of the gallant garrison were De Lisle's West Australians, who were scouting in front of Lord Kitchener's force, —an honourable post, because six regiments of regular cavalry were in that force. De Lisle's corps reached Pretoria on 28th August, and was thereafter employed in the Central Transvaal.
On 15th October the 1st contingent was inspected by Lord Roberts in Pretoria, and were complimented on their work. In November most of the 1st contingent sailed for home.