Royal Cornwall Hospitals NHS Trust was caring for 43 patients with coronavirus in hospital as of Sunday, figures show.
NHS England data shows the number of people being treated in hospital with Covid-19 by 8am on August 13 was up from 16 on the same day the previous week.
Across England there were 2,345 people in hospital with Covid as of August 13.
Nationally, the number of hospital patients with Covid-19 has more than doubled in the last four weeks.
The figures also show that 53 new patients with Covid were admitted to hospital in Royal Cornwall Hospitals NHS Trust in the week to August 11.