UEFA have decided to move Euro 2020 to 2021 and this has freed up space in June for the Champions League and Europa League to be completed, assuming sufficient progress is made in terms of containing the Coronavirus outbreak. At a videoconference meeting held on Tuesday, directors decided that the Champions League final should be held on June 27 and the Europa League final on June 24.

The Champions League final should still be held in Istanbul, as originally planned.

The original dates for both finals were May 30 and May 27 for the Champions League final and Europa League final respectively, but the Coronavirus postponements made it too difficult for the finals to go ahead on those dates.
Source: https://www.marca.com/en/football/international-football/2020/03/17/5e70cc62268e3eb92e8b45e5.html
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