How could Iran militarily close the Strait of Hormuz?

2. Unconventional tactics

In short, unconventional tactics , which is unpredictable and cannot be tackled in the military equations regularly, thereby undermining any counter-attack strategy.

A. Suicide attack,

The Iranian Islamic Guards Corps has put unconventional attacks on its strategy agenda. It has registered thousands of volunteers for suicide operations. Copies of the registration forms show that the "martyrdom-seekers" could volunteer for suicide operations against the targets. The registration forms also quote Khomeini's declaration that "[I]f the enemy assaults the lands of the Muslims and its frontiers, it is mandatory for all Muslims to defend it by all means possible [be it by] offering life or property," and current supreme leader Ali Khamene'i's remarks that "…….martyrdom-seeking operations mark the highest point of the greatness of a nation and the peak of [its] epic. A man, a youth, a boy, and a girl who are prepared to sacrifice their lives for the sake of the interests of the nation and their religion is a  [symbol of the] greatest pride, courage, and bravery." If the conventional means fail to address the  Iranian military goals in the Persian Gulf, suicide attacks may be put in the military agenda.

 B. Widespread Naval Mining

A naval mine is a self-contained explosive device placed in the water to destroy surface ships or submarines. These mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel. Naval mines can be used offensively—to hamper enemy shipping movements or lock vessels into a harbor; or block a waterway.During the Iran–Iraq War from 1980 to 1988, the belligerents mined several areas of the Persian Gulf and nearby waters. On April 14, 1988, the USS Samuel B. Roberts (FFG-58) allegedly  struck an Iranian M-08/39 mine in the central Persian Gulf shipping lane, wounding 10 sailors. In light of this experience  Iran may lay a lot of mines around the Strait of Hormuz to block it.

C. Drowning Large Tankers.

Finally, just by scuttling three or four large ships Iran can create an obstacle in the shallow Strait of Hormuz.  In other words, sinking four of their own empty tankers creates a marine hazard. So, there are many ways to block the strait.

The above summation  indicates  that any war is destructive for the International Community. Iran wants to cooperate with the IAEA and resolve its problems within a routine framework. Iran also has a strong political will to develop nuclear technology and advanced forms of energy to tackle global climate change,  long term energy needs and ameliorate the transition from a global dependency on fossil fuels to more advanced cleaner energy forms. In this context, it is possible for Iran and the IAEA to resolve all remaining issues according to the Work Plan on “Understanding of the Islamic Republic of Iran and the Agency on the Modalities of Resolution of the Outstanding Issues” (INFCIRC/711).

For all the above reasons, constructive dialogue is the only way to resolve suspicions created by  Iran’s nuclear program.  Acting within an accepted  framework and timetable, allows all states to contribute positively to a mutually desired goal, thereby reducing the military burden on all and contributing to comprehensive sustainable peace.  Iranians have an expression: "Destruction is very easy; the true challenge is to build and make something together". Or "one action of sanity renders one hundred sages busy".