People arriving into Scotland from Dubai will have to quarantine for 10 days from 4am tomorrow.
Anyone who has arrived in Scotland since January 3 also has to isolate for 10 days, from the date they arrived back into the country.
The Scottish Government says the change is due to a number of positive cases identified in passengers who have flown into Glasgow from Dubai since the start of the year.
It is unclear in the government's statement whether it applies to Celtic - who travelled to Dubai for a training camp before returning earlier this week.
But under normal circumstances, elite sportspeople are granted an exemption from quarantine rules if travelling abroad as part of their work, or for competition.
Officials also confirmed at the start of November that athletes could attend "elite training overseas" and be exempt from quarantine on return.
It was confirmed earlier today one of the club's players has Covid-19.
Holyrood says it is aware of the club's positive case and is providing advice - but when asked, would not directly confirm whether the quarantine period would apply to Celtic staff given the circumstances.
Transport Secretary Michael Matheson said: "It is evident, both in Scotland and in countries across the world, that the virus continues to pose real risks to health and to life and we need to interrupt the rise in cases.
"Imposing quarantine requirements on those arriving in the UK is our first defence in managing the risk of imported cases from communities with high risks of transmission. That is why we have made the decision to remove Dubai from the country exemptions list.
"Whether or not an overseas destination has been designated for quarantine restrictions, our message remains clear that people should not currently be undertaking non-essential foreign travel. People need to stay at home to help suppress the virus, protect our NHS and save lives."
All international travellers arriving into Scotland, apart from a very limited number of individual exemptions, must complete a passenger locator form and provide evidence that they have done so on arrival in the UK if requested to do so by a Border Force official.
This includes people arriving from countries where quarantine is subsequently not required.
Those who are found not to comply can be fined.