Taxi stands can be found near major hotels and in several locations just outside Old Town, but grabbing a taxi on the street, especially those parked in Old Town, usually comes with a premium fare. Always check the prices first, which should posted on the taxi’s right rear window. Taxis typically charge a starting fee plus a kilometre rate. Luckily the city government has implemented a law governing taxis and have put a cap on the starting fare (max. €5.50) and per kilometre rates (€1.10/km) - so even if you just hail a cab you shouldn’t be in for too much of a surprise. Ordering by phone is the best strategy though, as usually they have better rates. Note that the second (short) telephone numbers listed here will work from all Estonian fixed and mobile lines, but if you're calling from a foreign mobile, you need to dial the regular seven-digit number. Another option is to use one of the numerous taxi ordering apps like Taxify, Taxigo or Drivr to name a few. The often controversal Uber 'taxi' service is also availble in Tallinn.
Here’s a list of taxi companies along with their daytime base fares and per-kilometre rates. Night time metres can run about 20% more.