In order to use the Ühiskaart service in mTasku, you need to replace your regular SIM card with a more secure NFC SIM card. Currently, Telia is the only NFC SIM card provider in Estonia. Buy an NFC SIM card from the nearest Telia shop, the online store of Telia or the online store of Diil.
You can use Ühiskaart in mTasku with all phones running on Android 5.0 or newer operating system (except for Nexus, OnePlus and CAT), having an NFC support and an NFC SIM card installed. With Sony smartphones, you can use Ühiskaart in mTasku only if you are not using any other NFC-based payment apps (e.g. bank apps).
At present, only the contractual clients of Telia and Diil, as well as the users of the Diil, Super, Simpel calling cards can use Ühiskaart in mTasku. The clients of Telia and Diil can activate a previously NFC SIM card in the self-service. The users of Diil, Super, and Simpel calling cards must visit a Telia shop to activate an NFC SIM card. If you are a client of another operator, you must contact a Telia shop and select Telia or Diil as your mobile operator in order to obtain a SIM card with NFC support.