The Iranian navy has more than a dozen mini-submarines designed and purposed for these type of attacks.
https://www.navytimes.com/flashpoints/2018/11/29/iran-adds-2-mini-submarines-to-naval-fleet/
The Iranian navy has more than a dozen mini-submarines
The Saudis are well armed too. And they want us to go to war against Iran. My money is on MLB as the mastermind