As of writing this question, Israel and Saudi Arabia do not have any official diplomatic relations. Moreover, On 15 September 2020, Israel, the United Arab Emirates, and the Kingdom of Bahrain signed agreements establishing formal ties between the State of Israel and the two gulf countries.

Matt Yglesias, the blogger and journalist who currently writes at Slow Boring, predicted on December 28th that Israel and Saudi Arabia will establish diplomatic relations this year (70% confident).

Will Israel and Saudi Arabia establish official diplomatic relations in 2021?

This question resolves positively if Reuters, AP, NPR, the New York Times, the Wall Street Journal or the Financial Times reports to the effect that this has occurred at some point before the end of 2021.