You need a booster to cross the border via the causeway

The King Fahd Causeway Authority said the Kovid vaccine should take a booster dose to cross the border via the King Fahd Causeway connecting Riyadh, Saudi Arabia and Bahrain.

Vaccine relaxants and those who take the second dose within 3 months will be vaccinated. Although the law does not apply to children under 12, they must have insurance.