The is well over half of the 577MW installed offshore on the continent last year.
"Despite the financial crisis, offshore wind continues to be a major growth industry", said Justin Wilkes, Director of Policy at EWEA.
However, he warned that private wind developers were being held back by a lack of finance, and called on more loans from the European Investment Bank.
The figures showed that more than half of new turbines built during the first half of the year were off the coast of the UK.
Peter Madigan, head of Oofshore renewables at RenewableUK, said: "Offshore wind build-out is definitely picking up steam across Europe.
"It is an emphatic endorsement of wind energy as a technology, as countries such as Germany and Denmark, which already have significant onshore wind installations are now pursuing ambitious offshore plans."
Overall, 16 offshore wind farms totalling 3,972 MW were under construction in Europe during the period.
Of these, four became fully operational: Poseidon in Denmark, Alpha Ventus in Germany, Gunfleet Sands and Robin Rigg in the UK.