There have been so many visitors to the Blue Lagoon, Southwest Iceland, this February that guests without an advanced booking have not been allowed entry, ruv.is reports.
Up to 750 guests can visit the Blue Lagoon at one time.
More than 700,000 people visited the geothermal spa last year.
The Blue Lagoon is by far the most-visited tourist destination in Iceland.
UPDATED: An earlier version of this article stated that it is not necessary to book after 6 pm. This information, which appeared in the original RÚV article, was corrected after a representative of the Blue Lagoon contacted Iceland Review. Bookings for after 6 pm are also necessary.