The regional dust storms which are partly originated from drying Mesopotamia Wetlands (especially Hawizeh Wetland) had meaningfully amplified in the recent decades in Iran and Iraq, and initiated a lot of environmental problems in the impacted areas. Dust storms are cross-border phenomenon so an international solution (water diplomacy) is required to assess and them. The aim of this study is to assess the use of cooperative (partial bankruptcy theory) and non-cooperative (Nash method) game theory to assess environmental-water diplomacy for releasing water for Hawizeh Wetland environmental right considering different water allocation scenarios for Iran, Iraq and Turkey. The results indicated that the best option to encourage Turkey to release more water from the Tigris River for providing environmental water rights of Hawizeh Wetland is Iran-Iraq coalition which aims an integrated political and economic agreement with Turkey. By comparing cooperative and non-cooperative games, it was revealed that the non-cooperative method allocates larger shares of water to Iran than cooperative method. The offered routine for assessment of water diplomacy can be used to evaluate supplying environmental water rights for trans-boundary water resources.