Harold Watkin Thomas (19 February 1914 – 10 December 1989) was a Welsh dual-code international rugby union, and professional rugby league footballer who played in the 1930s and 1940s. He played representative level rugby union (RU) for Wales and Wales XV, and at club level for his native town of Neath, as a lock, i.e. number 4 or 5, and representative level rugby league (RL) for Wales, and at club level for Salford, as a second-row, i.e. number 11 or 12, during the era of contested scrums.