Portsmouth Hospitals NHS Trust, which runs the Cosham site, saw, treated or discharged 73 per cent of its patients within four hours in April.
The national target for A&E is 95 per cent.
Despite being below the target, April is the highest percentage the trust has achieved since last October, according to the NHS England data.
Over the winter months, QA Hospital dropped into the bottom 10 in the country with its lowest percentage in December at 66.2 per cent.
Nationally, the average for England in April was 85.7 per cent, with only 18 trusts reaching the 95 per cent target.