Morocco has ended its ban on unvaccinated visitors who can now enter the country with a negative PCR test.
The test must be taken no more than 72 hours before boarding the flight to Morocco.
Vaccinated visitors no longer need to take a COVID test.
In an update to its travel advice for Morocco, the Foreign Office says that to qualify as fully vaccinated visitors must have received a booster if the last dose of their vaccine was more than four months earlier.
Under 12s are exempt from COVID entry requirements.
The easing of restrictions is a boost for ABTA, which will hold its annual conference in Marrakech in October.
Registration for the three-day event opened earlier this month. It was originally due to take place in Marrakech in 2020.
All travellers to Morocco are required to download, print and sign a passenger health form before their arrival.
Random rapid antigen tests will be conducted upon arrival for selected groups of passengers. Additional PCR tests may also be required after 48 hours of arrival for randomly selected passengers.
The Moroccan government also re-opened its maritime borders for ferry services on 8 April and the borders with Ceuta and Melilla, the two autonomous cities of Spain on the border, were re-opened on 17 May.