File photo - UAE President Sheikh Mohamed bin Zayed Al-Nahyan welcomes Qatar s Emir, Sheikh Tamim bin Hamad al-Thani, at the presidential airport in Abu Dhabi on January 18, 2023. AFP
The two resource-rich monarchies restored official relations in January 2021, after the end of the nearly four-year diplomatic and transport blockade that isolated tiny Qatar.
"The United Arab Emirates and the State of Qatar announced the restoration of diplomatic representation between the two countries," said a statement on the UAE's official WAM news agency.
The sides are "resuming the work at the embassy of the UAE in Doha, and at the embassy of Qatar in Abu Dhabi and its consulate in Dubai", it said.
A similar statement was released by Qatar's foreign ministry.
Saudi Arabia, the UAE, Bahrain and Egypt imposed a diplomatic and transport blockade on Qatar in 2017, accusing it of supporting extremist organisations and becoming too close to Iran. Doha has denied the allegations.
The reopening of the diplomatic missions comes at a time of an easing in Gulf enmities after heavyweight rivals Saudi Arabia and Iran announced in March the end of a seven-year break in ties.
Among the round of reconciliation that has followed, Qatar and close neighbors Bahrain put aside a chronic feud to resume relations in April.
Saudi Arabia's Foreign Minister Faisal bin Farhan visited Iran on Saturday, meeting President Ebrahim Raisi, in another major step in their rapprochement. Iran reopened its Riyadh embassy this month.