Most Taxis here in Kalamata use this service, so by calling Radio Taxi Kalamata you will get your taxi within minutes.
You can also make a reservation, but this costs more and isn’t really necessary, as there are always enough taxis available around the clock.
Of course, you can also  always grab a taxi when you see one free passing by or waiting somewhere

Taxi in Kalamata isn’t so expensive as in other European countries. Within Kalamata you can go everywhere within the 5€ range.
For the airport, it’s about 15€