Travellers arriving in Scotland from Denmark, Iceland, Slovakia and Curacao will have to self-isolate for 14 days, the Scottish government has announced.
Justice Secretary Humza Yousaf said the measure was being put in place because of a "significant increase in cases" in the four countries.
The new quarantine rules come into force at 04:00 on Saturday.
In recent weeks, Portugal, Greece and Hungary have also been added to Scotland's quarantine list.
A list of countries exempt from the rules is available on the Scottish government website.
Mr Yousaf said: "Putting in place quarantine requirements on those arriving in the UK from various parts of the world is a key line of defence in our efforts to supress the spread of the virus.
"Managing the risk of importing cases from communities with high risks of transmission is vital in our efforts to do this.
"The advice remains that people should think very hard before committing to non-essential travel abroad. We are in the midst of a global pandemic and the situation in many countries can change suddenly."
Travellers face fines if they fail to comply with quarantine requirements after returning from abroad.