The new 154-bed field hospital, staffed by 55 doctors and 250 nurses, took 14 days to build and adjoins a quarantine camp.
Its large white tents house rows of hospital beds as well as a laboratory, pharmacy and X-ray machines.
Located off the Gulf state's east coast, it is the first crisis facility set up far from a hospital.
"This is done as a precautionary measure for COVID-19 patients in case they need to have ventilation and then ICU healthcare," Dr Nayef Louri told reporters at the facility. A fenced gate guarded by two police cars provides the only access to a dirt road that leads to the island that has been earmarked for development projects.