David "Dai" Thomas Harris (born 15 February 1879 – second ¼ 1958) was a Welsh rugby union, and professional rugby league footballer who played in the 1900s. He played club level rugby union (RU) for Treherbert RFC, as a centre, i.e. number 12 or 13, and representative level rugby league (RL) for Other Nationalities, and at club level for Wigan, as a centre, i.e. number 3 or 4.