Royal Cornwall Hospitals NHS Trust was caring for three 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 March 10 was up from one on the same day the previous week.
Across England there were 1,669 people in hospital with Covid as of March 10.
Nationally, the number of hospital patients with Covid-19 has decreased by 46% in the last four weeks.
The figures also show one new patient with Covid was admitted to hospital in Royal Cornwall Hospitals NHS Trust in the week to March 8.