Under pressure from rising patient numbers, some Dutch hospitals are transferring COVID-19 patients to German clinics.
The first ambulance left Rotterdam on Tuesday morning, a spokeswoman for the organisers of the transfers announced.
The first patient is to be admitted to the BG University Hospital in Bochum.
The patient was being treated in the intensive care unit at a hospital in Rotterdam.
Another patient transport was to follow later in the day, the spokeswoman said.
Hospitals in the German state of North Rhine Westphalia have space for a total of 20 patients from the Netherlands.
The patients are transported in specially-equipped ambulances, each accompanied by a doctor and a nurse.
Due to the rapidly increasing numbers of infections and patients, hospitals in the Netherlands are overwhelmed.
They are already warning of a state of emergency.
In many cases, necessary operations, even of cancer or heart patients, have been postponed because of a lack of nursing staff.
COVID-19 patients had already been transferred to Germany during the first waves of coronavirus infections last year.
The seven-day incidence in the Netherlands currently stands at more than 880.