David "Dai" John (born 24 November 1984 in Bridgend, Glamorgan) is a Welsh former professional snooker player.

In the first world ranking tournament of the season, the 2002 LG Cup, John secured a 5–3 win against Andrew Higginson before being eliminated in the following round by Martin Dziewialtowski.

In June 2003, John defeated fellow countryman Andrew Pagett 7–3 to retain the EBSA European Championship, becoming the first person to do so.

[4] In June 2015, John entered Australian Goldfields Open, defeating world number 44 Alfie Burden in the first qualifying round 5–1.

Although he was ultimately defeated by Peter Lines by the same score in the following round, this performance encouraged John that he could still make a full-time return to the game at a professional level.