It is the first time the regulator has provided a right-of-way grant for an offshore wind project.
As well as connecting Deepwater Wind's project to land at Block Island, it will also connect it to the mainland grid for the first time.
While BOEM has approved the provision of a right-of-way grant, the body still has to agree a rate for the rental of the seabed with Deepwater. The developer will then be required to pay the first year's rent upfront.
In September, the transmission network also received federal approval from the US Army Corps of Engineers.
The project is located five kilometres off the US east coast. It will feature five 6MW Alstom Haliade turbines on jacket foundations and is due to come online in 2016.