He reached the second round of the PDC World Championship for the first time in 2012. In a tight game against number fourteen seed Ronnie Baxter, Farmer trailed 1–2 in the best-of-five-sets match. He then produced some of his best darts by hitting five 180's in taking six of the final eight legs to seal a 3–2 victory. He continued his run by beating German qualifier Kevin Münch in the second round, but was then whitewashed 0–4 by world number three James Wade in the last 16. In March he hit a nine-dart finish in the third UK Open Qualifier during a first round match against Andy Relf. Farmer was knocked out in the last 16 of the event by Andy Smith. Farmer lost in the preliminary round of the UK Open 1–4 to Jamie Lewis, and reached the last 16 once more in his final ten tournaments of 2012, at the penultimate Players Championship where he was beaten by Gary Anderson 6–1.