The United Arab Emirates is joining an international maritime mission to protect commercial shipping in the Strait of Hormuz and other areas, state news agency WAM said on Thursday.
The operation area for the International Maritime Security Construct covers the Strait of Hormuz, Bab al-Mandab, the Sea of Oman and the Arabian Gulf, WAM said.
Saudi Arabia said on Wednesday it would join the same coalition.
Several oil tankers have been attacked in Gulf waters this year. Washington and Riyadh have blamed Iran for the explosive blasts, a charge Tehran denies.