Cornwall Partnership Trust was caring for nine patients with coronavirus in hospital as of Tuesday, figures show.
NHS England data shows the number of people being treated in hospital with Covid-19 by 8am on May 31 was up from seven on the same day the previous week.
There were six beds occupied by patients with Covid-19 four weeks ago in Cornwall Partnership NHS Foundation Trust.
Across England there were 2,780 people in hospital with Covid as of May 31, with 77 of them in mechanical ventilation beds.
Nationally, the number of hospital patients with Covid-19 has decreased by 39% in the last four weeks, while the number on mechanical ventilators has decreased by 38%.
The figures also show that nine new patients with Covid were admitted to hospital in Cornwall Partnership NHS Foundation Trust in the week to May 29. This was the same number as in the previous seven days.