Amir Hossein Akbari opened the scoring and Hamid Behzadpour and Mohammad Masoumizadeh (twice) scored for Marco Octavio’s team.
Lebaste and Zaveroni were on target for Tahiti.
Iran national beach soccer team will face Russia on Thursday.
Group A consists of the UAE (host), Brazil, Egypt and Spain.
The tournament, which is organized by the Dubai Sports Council (DSC) and Beach Soccer Worldwide (BSWW), got underway in Dubai on November 6 and will finish on November 10.