Enbridge has acquired the stake for C$750 million (€525 million) ($573 million). E.on will hold a 50.1% stake.
The UK's Green Investment Bank now also owns a 25% stake valued at £306 million (€432 million) after originally acquiring an initial 19% stake back in May.
For investments over £300 million, the GIB needs approval from its major stakeholder, the UK government. GIB upped its stake in Rampion once the approval was given.
It is Enbridge's first investment in offshore wind, but it has invested in over 2GW of onshore wind projects in the US and Canada.
Enbridge holds 80% stakes in two 200MW US onshore projects in Texas and Indiana, which E.on operates.
The Rampion project will consist of 116 MHI-Vestas V112-3.45MW turbines. It is located 13km off the UK's south coat and is due for completion in 2018.