Just 37% are taking 30 minutes from dropping a patient off to being back on a call.
One in four ambulances are meeting turnaround targets at the Midlands Regional Hospital in Tullamore.
The Health Information and Quality Authority set out a thirty minute window for an ambulance to deliver a patient and return to service.
The number of services achieving the time in Mullingar is 37% and 55% in Portlaoise.
Just over a third of ambulances reached the standard time across the country.