Wales fans have been SLOTXO turned away from Amsterdam ahead of Saturday's Euro 2020 tie against Denmark.
The Netherlands currently bars non-essential visitors from the UK.
But Wales supporters said they had been treated unfairly after travelling to Amsterdam from Azerbaijan.
Jamie Shipp, 30, of Pontypridd said: "Surely our Covid risk should be based on having spent the previous 15 days in Baku, not because we are British nationals."
Danish fans can enter the Netherlands if they stay in the country for less than 12 hours as part of an exemption to the entry rules for EU and Schengen area residents.
The exception does not apply to Wales fans, following Brexit.
Mr Shipp and his friend James Lewis spent just over a fortnight in Azerbaijan to watch Wales' opening two games of the European Championships.
They did not travel to Rome for the final group game, but remained in Baku before heading for the last-16 tie in Amsterdam, via Moscow.
However, they said they faced an "interrogation" upon their arrival at Schiphol Airport and were made to feel like "criminals".
"As soon as we landed we were taken to one side and questioned by border control about why we were there," said Mr Lewis, 30, of Gilfach Goch.