From Wikipedia re. Saudi Arabia
Religious freedom is virtually non-existent. The Government does not provide legal recognition or protection for freedom of religion, and it is severely restricted in practice. As a matter of policy, the Government guarantees and protects the right to private worship for all, including non-Muslims who gather in homes for religious practice; however, this right is not always respected in practice and is not defined in law.Moreover, the public practice of non-Muslim religions is prohibited. The Saudi
Mutaween (
Arabic:
مطوعين), or
Committee for the Propagation of Virtue and the Prevention of Vice (i.e., the religious police) enforces the prohibition on the public practice of non-Muslim religions.
Sharia Law applies to all people inside Saudi Arabia, regardless of religion.
So, it appears one may practice whatever religion they want in privacy.
"As a matter of policy, the Government guarantees and protects the right to private worship for all, including non-Muslims who gather in homes for religious practice; . . ."
But, watch out.
" . . . however, this right is not always respected in practice and is not defined in law."