David "Dai" Thomas Harris (15 February 1879 – 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, and representative level rugby league (RL) for Other Nationalities, and at club level for Wigan, as a centre.

[2][4] Dai Harris was born in Morriston, Wales, he was a blacksmith's assistant.

Dai Harris won a cap, playing at centre and scored the third try, for Other Nationalities in the 9–3 victory over England at Central Park, Wigan on Tuesday 5 April 1904, in the first ever international rugby league match.

[5] During Dai Harris' time at Wigan, they won the South West Lancashire League in 1904–05.