It depends on the circumstances, but generally, if you keep your beliefs strictly to yourself and do not use any religious paraphernalia, e.g. Bibles, rosaries, small shrines, specific religious clothing, you should be alright. However, it takes very little to get the entire Saudi infrastructure against you.
1) People Other Than Sunni Muslims and Jews: If you are a person who enters Saudi Arabia already being something other than Sunni Muslim, e.g. Christian, Hindu, Buddhist, Shiite Muslim, etc., with the only two exceptions being if you are an Atheist or a Jew, the government punishes overt expressions of religion. In the case of Atheism, Saudi Arabia does not recognize the concept of Atheism and, therefore, will consider you to belong to whatever religion your ancestors had before you. For example, an Atheist Dane will be considered a Christian by the Saudi Authorities since Danes were historically Christians. As for Jews, there are distinct issues, which will be addressed separately.
An overt expression of religion (other than Sunni Islam) that is punishable by the Saudi government includes: (1) having a center/place of worship, (2) possessing, moving, or selling any religious paraphernalia and (3) attempting any form of proselytization, up to and including interfaith dialogue or open discussion on a religion other than Sunni Islam. In the case of Atheism, any clear expressions of Atheism or criticism of Islam, Allah, or Muhammad, are punishable, as is any attempt to convince someone of the merits/correctness of Atheism.
2) Jews: If you are a person who is a Jew, it is likely that you will be banned outright from Saudi Arabia. Prior to 2005, the website for the Saudi Embassy in the United States explicitly stated that visas to Saudi Arabia will not be issued for Jewish Americans (on account of their Judaism and regardless of whether or not they were also Israeli citizens or had even visited Israel). Historically, Saudi Arabian companies have explicitly required that partners of theirs who do work in Saudi Arabia refrain from bringing foreign Jews to the country and will not issue them work permits. Of course, any overt expression of Judaism in Saudi Arabia is punishable and overt expression is the same definition as for other Non-Muslim groups. However, violations will be punished more severely in the case of Judaism.
3) Apostates: If you are a person who was born a Sunni Muslim but is no longer a Sunni Muslim because you decided to leave the faith, the punishment according to Saudi Law, assuming that you are sane and made the decision of your own free will to leave Islam, is death, either by firing squad or gallows. Saudi Arabia usually enforces this when the apostate makes a clear declaration of his apostasy, usually a statement on the internet or a mention of his beliefs to his family who in-turn report him. Additionally, conversion from Sunni Islam to any other religion (including Shiite Islam) is strictly prohibited. If a conversion is discovered, both the apostate and the person who presided over the conversion are liable to the Saudi government.
Mecca (Makkah) in Saudi Arabia.
There has not yet been a female ruler of Saudi Arabia.
absolutely
be a muslim
Arab Muslim.
No you Dont!!
yes
The vast majority of Saudi are Wahhabi Muslims. Being any religion other Muslim is illegal in Saudi Arabia.
Arabia now known as Saudi Arabia .
Arab Muslim.
Islam, since being a citizen of Saudi Arabia legally requires you to be a Muslim.
Indonesia has the largest Muslim population.