Welsh Regiment in WWI – Research Guide

The Welsh Regiment gives family historians an unusually rich collection of clues because its First World War battalions were shaped by very different recruiting traditions, numbering systems and operational paths. This page explores how Army service numbers — and particularly the prefixes sometimes attached to them — can help separate soldiers belonging to different parts of the regiment’s enormous wartime expansion. Some of those prefixes open a route into the distinctive world of locally raised Pals formations, where battalion identity could be closely connected with particular Welsh communities, while other Service Battalion soldiers leave a less immediately obvious trail. The regiment’s Territorial Force creates a completely different research problem, challenging some of the assumptions normally made about where a mobilised Territorial soldier might have served and, in one case, potentially leading backwards into an earlier Yeomanry connection. The Regular battalions add another sharp geographical contrast, making the precise battalion just as important as the regimental name when interpreting an overseas photograph, campaign reference or family story. Recruitment geography, medal records, casualty evidence and surviving service fragments can then be used to test these different possibilities against an individual soldier. For researchers beginning with a name, Army number, medal index card, battalion reference or Welsh family connection, this hub shows why apparently small details — especially a number prefix or battalion designation — can be enough to send the investigation down a completely different First World War path.

Territorial Welshmen – But Not on the Western Front

The Territorial Force battalions of the Welsh Regiment did not serve on the Western Front, creating an important distinction for anyone researching a Welsh Territorial soldier. The 4th and 5th Battalions served in the Eastern Mediterranean, where they shared part of their geographical story with the regiment’s 1st Regular Battalion. The 6th and 7th Territorial Battalions, by contrast, were Home Service formations, meaning that a Territorial connection could lead either overseas or remain firmly within Britain.

The 24th Battalion adds another layer of complexity. It was created in 1917 through the conversion of the Pembroke and Glamorgan Yeomanry, bringing men from a mounted Territorial background into the Welsh Regiment before serving in the east. For family historians, this makes Territorial identification particularly valuable but not necessarily straightforward. A Welsh Regiment Territorial soldier should not automatically be searched for in France and Flanders, while a 24th Battalion connection may require research into an earlier Yeomanry career. The regiment’s Territorial story therefore ranges from Home Service to the Eastern Mediterranean and from infantry origins to converted cavalry, despite sitting beneath the same regimental title.

A Service Battalion Numbering System Full of Prefixes

The Welsh Regiment’s Service battalions provide an unusually rich set of Army service-number clues. The earlier 8th, 9th, 10th and 11th Service Battalions generally used numbers without a distinctive battalion prefix. The later formations, however, present a very different picture. Men associated with the 13th through 19th Battalions can appear with prefixes directly identifying their battalion — such as 13/ or 15/ — while the W/ prefix was also used.

This reflects the distinctive origins of these later formations. Several were Pals battalions, raised around particular Welsh communities and identities, including Rhondda, Cardiff City and Glamorgan. For genealogists, a prefix can therefore reveal considerably more than a simple administrative numbering convention: it may point towards a particular wartime-raised battalion and the community from which that formation emerged. The coexistence of battalion-specific prefixes, W/ numbers and unprefixed Service Battalion numbers nevertheless demands careful interpretation. A Welsh Regiment number cannot be approached through one universal rule, but where the right prefix survives it can provide an unusually direct route towards narrowing a soldier’s place within the regiment’s enormous wartime expansion.

The 2nd Battalion and the Major Battles of the Western Front

While the regiment’s Territorial battalions followed very different paths, the 2nd Battalion, Welsh Regiment provides a strong connection with the Western Front. As a Regular battalion, its wartime experience stretched across much of the conflict and included some of the defining battles and campaigns fought by the British Army in France and Belgium.

Its story reaches from Mons and Loos through to the Somme and Passchendaele, meaning that an individual soldier’s 2nd Battalion service could potentially belong to very different phases of the war. Establishing when a man joined or left the battalion is consequently essential before associating him with any particular battle. This also creates a striking contrast within the regiment’s Regular establishment: while the 1st Battalion served in the Eastern Mediterranean, the 2nd was engaged extensively on the Western Front. For family historians, simply establishing that an ancestor was a pre-war or wartime Regular in the Welsh Regiment is therefore not enough to determine his likely theatre. The battalion number can completely transform the geographical direction of the research, separating an eastern service story from one extending through many of the British Army’s best-known battles in France and Belgium.

Explore similar units:

1. Royal Welch Fusiliers: Another of the prominent infantry regiments from Wales
2. South Wales Borderers: A Welsh regiment within a similar recruitment area
3. Royal Scots: Another 'national' regiment based within Great Britain

Click here to explore similar infantry regiments in the main WWI Infantry Regiment Library.

Click here to explore regiments from the same geographical region.