Dee ihe na-aga n'ihu maka paragraf a - N'egwuregwu Olimpik nke 2012 na London, Halsall gbara asọmpi n'ihe ise. Halsall erutela ọkara-ikpeazụ n'asọmpi 100m butterfly
, na-etinye oge nke 58.52, nke ọma site na oge kachasị mma nke 57.56 setịpụrụ na Machị. Halsall mere njedebe nke 100m freestyle na 50m freestyle, na-emecha 6th na 5th n'otu n'otu. N'egwuregwu 4×100 m freestyle Halsall gbara agba nke abụọ n'oge 53.29, na-enyere ndị otu Briten aka inweta ọkwa nke ise. N'ikpeazụ nke 4 × 100 m medley relay ndị otu ndị Britain kwụsịrị nke asatọ, ebe Halsall na-enye ụkwụ arịlịka nke 54.08.