Figures from the European Wind Energ Association (EWEA) show that Europe's offshore industry installed a record 2.3GW in the first half of 2015, more than triple the amount installed in the same period last year.
Germany installed 406 turbines, increasing its offshore capacity by 1.7GW, followed by the UK (522MW) and the Netherlands (114MW).
The European offshore market now stands at 10.4GW across 82 projects and 11 countries, according to the industry body.
"It has taken the offshore wind industry just six months to set the best year the sector has ever seen in terms of installed capacity," said EWEA chief policy officer Kristian Ruby.
"While this clearly shows a commitment to offshore wind development in Europe, a number of completed projects, explosive growth in Germany and the use of higher capacity wind turbines are major contributors to these numbers," Ruby added.
Despite strong offshore development, onshore net installation in Germany fell 34% year-on-year to 1.1GW for the first half of 2015, made up from 443 turbines. But the German engineering federation (VDMA) still expects the total for 2015 to finish with 4GW onshore installations.
Despite the fall, said VDMA, the first half of 2015 was still the second best ever period in Germany's wind industry.
German manufacturers Nordex and Senvion have unveiled their domestic installation levels. Senvion said it installed 285MW of wind turbines in the first six months of 2015 in Germany. The firm said it installed 100 turbines in the period, it was the second largest manufacturer in Germany.
Nordex claimed an 11.8% market share in Germany with 140MW and 57 turbines installed in the country.