Thomas Llewellyn was a Welsh rugby union and professional rugby league footballer of the 1900s and '10s, playing club level rugby union (RU) for Treherbert RFC, and playing representative level rugby league (RL) for Great Britain, and Wales, and at club level for Oldham, as a centre, i.e. number 3 or 4.
Tom Llewellyn won caps for Wales (RL) while at Oldham in 1908 2-caps, and won caps for Great Britain (RL) while at Oldham in 1908 against New Zealand (2 matches).
Tom Llewellyn played centre, i.e. number 4, in Oldham's 3–7 defeat by Wigan in the Championship final during the 1908–09 season at The Willows, Salford on Saturday 1 May 1909.
Tom Llewellyn played centre, i.e. number 4, in Oldham's 9-10 defeat by Wigan in the 1908 Lancashire Cup final during the 1908–09 season at Wheater's Field, Broughton, Salford on Saturday 19 December 1908.