The region built 13 new offshore wind farms in 2017, a total of 3.1GW, out of which the UK installed 1.7GW.
The total capacity in Europe now stands at 15.8GW, with a further 11 projects in the UK and Germany expected to boost capacity to 18.7GW.
Offshore wind is projected to grow to a total installed capacity of 25GW by the end of the decade.
The average size of new turbines also increased to 5.9MW – a 23% rise on 2016.
CEO Giles Dickson said: “A 25% increase in one year is spectacular. Offshore wind is now a mainstream part of the power system and the costs have fallen rapidly. Investing in offshore wind today costs no more than in conventional power generation.
“It just shows Europe’s ready to embrace a much higher renewables target for 2030. 35% is easily achievable. Not least now that floating offshore wind farms are also coming on line.”