Passport holders from Bahrain, Kuwait, Oman, Qatar and United Arab Emirates can enter without any problem.
There is an evisa that allows visits of up to 90 days for tourists from European Union, Andorra, Australia, Brunei, Canada, China, Hong Kong, Iceland, Japan, Kazakhstan, Liechtenstein, Macau, Malaysia, Monaco, Montenegro, New Zealand, Norway, Russia, San Marino, Singapore, South Korea, Switzerland, Taiwan, Ukraine and United Kingdom.
A visa on arrival is available for the same visitors as the eVisa. Passport holders who have a Schengen, UK or US visa that has an entry stamp and is still valid may gain a visa on arrival.
Saudi eVisa
Saudi travel regulations
Saudi Arabia visa information
Saudi Arabia embassies and consulates