What is the minimum distance between Israel and Saudi Arabia?

The two closest points are in the Gulf of Aqaba -- the southern-most point of Israel (at the border with Egypt) and the northern-most point of Saudi Arabia (at the border with Jordan). The distance between these two points is 15.87km (9.86 miles) as the crow flies, using the calculator on this website:

https://www.distance.to/29.357341770915184,34.96115684509277/29.490600079108667,34.90264177322388

If you go by the extended borders into the recognized territorial waters of the Gulf of Aqaba, the distance is shortened by 4 mile than if you used the closest points of land. As stated by gtho4, the closest land distance is 9.86 miles (15.87km), the closest point between the recognized borders if extended into the territorial waters of the Gulf of Aqaba is 5.85 mi (9.41 km).

https://www.distance.to/29.37518197120462,34.884434938430786/29.45349969484501,34.921159744262695