Four years after competing in his first Olympics, Brandl qualified for his second Austrian team, as a 25-year-old, at the 2012 Summer Olympics in London, by attaining a B-standard time of 1:48.95 in the men's 200 m freestyle. He challenged seven other competitors on the third heat of his only individual event, including Canada's Blake Worsley and Israel's Nimrod Shapira Bar-Or. He came only in fifth place by 0.68 of a second ahead of Tunisia's Ahmed Mathlouthi, with a time of 1:49.00. Brandl, however, failed to advance into the semifinals, as he placed twenty-seventh out of 41 swimmers in the morning's preliminary heats. Two days later, Brandl reunited with his teammates Rogan, Janistyn, and Christian Scherübl for the men's 4 × 200 m freestyle relay. Swimming the lead-off leg, Brandl recorded a time of 1:49.80, and the Austrian team went on to finish heat two in eighth place and sixteenth overall, for a total time of 7:17.94.