There is no national religion on Antarctica, because there are no countries there. People who practice every religion on earth may, however, live and work there temporarily.
As Antarctica is generally uninhabited by people, no religion has been declared.
Antarctica like america has different religions
There is no common religion in Antarctica. Workers in scientific stations -- the only humans in Antarctica -- bring their religions with them from their native countries and worship accordingly.
There are no countries on Antarctica and no permanent population, therefore, there is no requirement for it to have a religion.
Since there is no permanent population on the continent, no 'predominant religion' exists.
No one lives there... so there is none!
Antarctica.
You could find a believer of every religion on earth in Antarctica among the temporary workers and scientists there.
Antarctica has no native population. Scientists from all over the world do research there. Those scientists represent a large number of religions.
Generally, people who work in Antarctica -- paid for by their governments in search of science -- are not sorted out by religion. Otherwise, no one lives in Antarctcica.
One definition of the word religion is world view. Any person interested in expanding his/her world view would want to explore Antarctica.
People who work in support of science on the Antarctic continent, practice the religion they carried with them to their workplace.