As President Donald Trump warns Iran against using mines to threaten oil tankers in the Strait of Hormuz, the U.S. Navy’s purpose-built minesweepers are sitting stateside thousands of miles away with no plans to put them to use while the war rages on. As gas prices in the U.S. continued to skyrocket, Trump on Tuesday took to Truth Social to demand that Tehran “immediately” remove any mines placed in the vital seaway and to do so “forthwith” lest the Iranian military suffer “consequences … at a level never seen before.” That warning came after multiple news outlets reported Iran had begun mining the strait, a narrow waterway that is the only passage from the Persian Gulf into open ocean. He also threatened to use drone strikes to “permanently eliminate any boat or ship attempting to mine the Hormuz Strait” and boasted of having done so against 10 Iranian “inactive mine-laying boats” in a separate post several minutes later.


I think a sea mine is a bit big for a drone
Wouldn’t be that hard to develop and build a sea drone that is a mine.
A drone with a heavy explosive payload that could be remotely piloted into the desired position, then submerged just under the water and hold that position, waiting to trigger.
It would need to come in two pieces: a flotation/propulsion/payload upper segment and an anchor/ballast lower segment. Lower segment is basically a big hollow anchor filled with air. When filled with air, the whole thing is easily buoyant enough to float freely and move around. When ready to deploy, fill the anchor segment with water, making it much heavier and sinking it to the bottom. Have a cable on a winch connecting the two sections. Once the anchor hits the sea floor, reel in the winch until the upper segment begins to sink. Stop the winch when the upper segment reaches the desired depth. The upper segment needs to be buoyant, but not buoyant enough to lift the anchor off the bottom. Once in place, you can shut off most of the electronics and only have a vibration/magnetic/mechanical/whatever trigger waiting to detonate the payload. (If you want to be more elegant and ethical about it, also have it operate the winch to resurface on a regular basis to expose its antenna and listen for a disarm signal.)
Depends on how big the drone is.
I guess it could be those naval drones Ukraine uses.