Donna Nook will close its seal viewing area and booking system from Thursday as Lincolnshire prepares for the second national coronavirus lockdown.
Bookings will be accepted for dates up to and including November 4, after which Lincolnshire Wildlife Trust is asking people not to travel to see the seals.
Refunds will be given for all bookings received for dates on or after November 5.
A decision about when and how to reopen will be taken once guidance for the post lockdown period has been announced by the government.
Two adorable pups were born recently with the number continuing to increase and the warden will be doing weekly counts.
There are 54 pups, 108 cows and 26 bulls, according to the latest count on October 30.
Lincolnshire Wildlife Trust said: “We would like to thank everyone for the messages of support and their interest in the seal colony.
“However, we would reiterate the importance of following Government guidelines and not visiting the seals during the lockdown period.
“Staff will continue to be present on site to manage the situation and monitor the colony. We’ll also continue sharing a weekly pupdate and photos of the seals on our Facebook page so be sure to give us a follow.
“As a charity, we’ve been hit hard by the coronavirus pandemic. Wildlife needs your help now more than ever. Please, if you can, donate to our seal appeal and help us to keep protecting the seals and their important habitat.”