Manchester City's Phil Foden and Manchester United's Mason Greenwood have each been fined 250,000 Icelandic Krona (£1,300) after breaching the country's coronavirus rules.
Icelandic police have confirmed the fine has been issued and the duo apologised to officers for their actions after leaving England's bio-secure bubble.
Foden and Greenwood are alleged to have met two girls in another area of the hotel the Three Lions were staying in.
England travel to Denmark on Tuesday evening for their second Nations League game after the 1-0 victory in Iceland. They do so without Greenwood and Foden - who have been axed from Gareth Southgate's squad.
The FA has launched a "full investigation" into the incident and also apologised to the Football Association of Iceland.
An FA spokesperson said: "Whilst in Iceland, both Phil Foden and Mason Greenwood spent time outside of our private team area, which was a breach of our Covid-19 rules.
"While they did not leave the team hotel, it was an unacceptable breach of our protocol. They have both apologised for their serious lack of judgement."
Should the FA also fine Greenwood and Foden? Have your say here.
And Three Lions boss Southgate confirmed the "naive" duo did not come into contact with any other members of the squad during a press conference on Monday.
"Two of the boys have broken the Covid-19 guidelines, in terms of our secure bubble," he said.
"We had to decide very quickly that they couldn't have any interaction with the rest of the team and wouldn't be able to train.
"Obviously they have been naive. We have dealt with it appropriately. I recognise their age but the whole world is dealing with this pandemic.
"Now they will have to travel back to England separately. Nothing has happened in the areas we occupy in the hotel."
Meanwhile, City and United have expressed their disappointment in their players' actions. City said Foden's behaviour was "totally inappropriate" and "fell well below the standard expected of a Manchester City player and England international".
And Manchester United said they are "liaising with the Football Association and are disappointed with the actions of Mason Greenwood".
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