The constitution of Namibia allows for freedom of religion and the country is a secular state. It is thought that around 90% of Namibians are Christian. The largest Christian group is the Lutheran Church which grew out of the work of the Finnish Evangelical Lutheran Mission. Next largest are Roman Catholics, while most other Christian denominations can also be found.
Other religions that are practiced in the country include Judaism, Islam, Buddhism, and the Baha'i Faith (and there is even a rumour that their may be one atheist lurking somewhere in the country).
On a serious note whatever your religious persuasion you will be warmly welcomed in Namibia.
"In religion and politics, people's beliefs and convictions are in almost every case gotten at second hand, and without examination." Mark Twain