In event finals, she finished fifth on floor with a score of 13.800. At the end of May, Tunney participated in the British Teams competition which acted as the first Olympic trial. She helped her club, City of Liverpool, win first place with the highest all around score of 56.550. In event finals, she placed second on vault scoring 14.750, first on uneven bars scoring 14.700, fifth on balance beam scoring 13.600, and second on floor scoring 13.500. At the beginning of June, Tunney competed at an international friendly with gymnasts from Finland and Spain in Ipswich, United Kingdom which was also the second Olympic trial. She won the all around competition with a score of 56.500. At the end of June, Tunney competed at the British Championships in Liverpool, United Kingdom. This is the third and final Olympic Trial to decide the gymnasts that will represent the United Kingdom at the Olympics. She won the all around competition with a score of 56.750. She said, "It’s totally unexpected to win. The main focus with it being the Olympic trial was to stay clean and I thought if I did that I could get maybe in the top 5 but to win is incredible. The trials have all gone really well for me so it’s now just up to the selectors to decide what works best for the Olympics. The first year as a senior couldn’t have gone better really and I’m really enjoying competed in front of big crowds. Having won the junior title last year and moved straight up to win seniors is brilliant, I’m very happy." In event finals, she placed second on uneven bars scoring 14.350, fifth on balance beam scoring 13.550, and fourth on floor scoring 13.500. At the beginning of July, Tunney was selected to compete for the United Kingdom at the 2012 Summer Olympics, making her the youngest athlete for Team GB at London 2012. After arriving in London, she said, “It’s been overwhelming, definitely, I wasn’t expecting it to be like this. I knew it was going to be big but this was more than I expected. But I’ve got all my team-mates to settle me down and talk me through things. Being in the village has been the best bit – how big it is, and seeing other athletes, great athletes, walking around. The others have tried to calm me down.”