The developer has structured $290 million in financing through institutions such as French bank Societe Generale and the US-based KeyBank National Association.
Deepwater Wind will now be able to move forward with the construction of the project, located off Rhode Island, north-east US.
Block Island will use five Alstom 6MW Haliade turbines, currently in production in France. According to Deepwater Wind, the 15 blades have all been manufactured in Denmark.
The developer also said its steel jacket foundations are in the process of being built by Gulf Island Fabrication, at its facility in Louisiana, southern US.
Offshore construction is due to begin this summer, with commissioning expected towards the end of 2016.
Block Island now looks set to become the US' first commercial offshore wind project. In comparison, the troubled 468MW Cape Wind project in Massachusetts ended its two-year $4.5 million lease for port facilities in New Bedford.