The project is expected to generate 3.2GW of electricity by 2027, more than 1GW of which will be green hydrogen.
It is currently in its first phase of permitting, with grid connection and environmental impact assessments also underway.
AquaTerra Energy and Seawind will jointly develop the wind and hydrogen assets.
Seawind Ocean Technology CEO Dimitrios Moudouris said: “We are pleased to partner with Aquaterra Energy in these highly impactful projects in Italy and Greece.
“We consider the Mediterranean to be the best area where significant offshore wind projects can be developed and cross-border synergies can be made, serving Europe and the Middle East and North Africa (MENA).
“Aquaterra Energy has displayed its expertise and commitment to green hydrogen through existing projects and we identified an experienced partner to enable us to accelerate our ambitious offshore wind and hydrogen project development strategy.”
Aquaterra Energy will provide its offshore engineering and green hydrogen production knowledge for the HyMed project, while Seawind will offer its expertise in floating offshore wind technology.
Aquaterra Energy Renewables director Anne Haase said: “With governments and business recognising the value of hydrogen as a vital resource for net zero initiatives, energy security, and guarding against volatile natural gas prices, we are hugely excited by the opportunities for production presented by this new partnership.
“Seawind’s fully integrated and scalable floating wind model offers a clear path to cost-effective industrial scale production – and we are delighted to be able to provide the final piece of the production puzzle for it.”
Founded in 2005, Aquaterra Energy has helped develop more than 1,000 offshore projects to date in the North Sea, West Africa, South-East Asia, the Caribbean and Australia.