How can you find out if your taxi is indeed a legal taxi?

In accordance with EU & GR law, a taxi or minibus taxi should have the following:

The number plates should be YELLOW and should be like the following example: TAZ–9999. In Crete the 3 letters are “TAZ” ( in Heraklion should have: “TAE”).
The exterior colour: In Crete the exterior colour of a taxi must be (depending the registered area of work): Blue (taxis of Chania municipality) – White (Rethymnon municipality and some areas in Heraklion) – Silver or Grey (Most common colour – found in most parts of Crete).
ALL Taxis obligate by law to be equipped with: a Taximeter, a “Taxi” or “Radiotaxi” roof sign, a “free for hire” sign in the right side of the dashboard, an Electronic Recognition Label – ERL – (it is a small round sticker containing a microchip, placed at one corner of the windshield)