Cornwall Partnership Trust was caring for 37 coronavirus patients in hospital as of Wednesday, figures show.
NHS England data shows the number of people being treated in hospital for Covid-19 by 8am on October 5 was up from 10 on the same day the previous week.
The number of beds at Cornwall Partnership NHS Foundation Trust occupied by people who tested positive for Covid-19 more than doubled in the last four weeks – 28 days ago, there were 13.
Across England there were 9,631 people in hospital with Covid as of October 5, with 195 of them in mechanical ventilation beds.
The number of Covid-19 patients hospitalised nationally has increased by 98% in the last four weeks, while the number on mechanical ventilators has increased by 67%.
The figures also show that 34 new Covid patients were admitted to hospital in Cornwall Partnership NHS Foundation Trust in the week to October 3. This was up from 14 in the previous seven days.