The exercises aim "to display the country's military might and readiness to confront our enemies," a spokesperson for the Zolfaqar-1400 drill said.
Iran's military has launched an annual exercise near the mouth of the Gulf, a few weeks before the resumption of talks between Tehran and world powers to revive a 2015 nuclear deal.
"The military exercise in Iran's coast on the Gulf of Oman is to display the country's military might and readiness to confront our enemies," Admiral Mahmoud Mousavi, the spokesman for the Zolfaqar-1400 drill, told state TV on Sunday.
The exercise covers an area from the eastern parts of the Strait of Hormuz to the northern parts of the Indian Ocean and parts of the Red Sea, state TV reported.
About a fifth of oil that is consumed globally passes through the strategic Strait of Hormuz waterway in the Gulf.
Periodic confrontations have taken place between Iran’s military and US forces in the Gulf since 2018, when former US President Donald Trump exited the nuclear pact and reimposed harsh sanctions against Tehran.
Iran has reacted by breaching the deal's limits on its nuclear programme.
Indirect talks between Iran and US President Joe Biden's administration to revive the pact, which were put on hold since the election of Iran's hardline President Ebrahim Raisi in June, are set to resume in Vienna on November 29.