Royal Surrey County Hospital Trust was caring for 13 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 July 30 was up from four on the same day the previous week.
Across England there were 1,526 people in hospital with Covid as of July 30.
Nationally, the number of hospital patients with Covid-19 has increased by 34% in the last four weeks.
The figures also show that 12 new patients with Covid were admitted to hospital in Royal Surrey County Hospital NHS Foundation Trust in the week to July 28.