Sweden's Northern Offshore Services (NOS) has clinched a charter deal for seven crew transfer vessels (CTVs) with Danish renewables giant Orsted.
The company said the agreement increases its presence on the British west coast in the wind farm sector.
The charters will cover the next three years, with the first vessels starting their deals at the beginning of this year.
Others will "gradually" join Orsted until the summer.
The CTVs will operate on the Walney, Walney Extension, West of Duddon Sands, Barrow, Burbo Bank and Burbo Bank Extension offshore wind farms.
Orsted's operations sites in Barrow and Liverpool will be base ports. No financial terms have been released.
Reward for long service
NOS chief commercial officer Fredrik Hallqvist said: "We are pleased to have been selected for this scope, and this award is based on many years of good cooperation between NOS and Orsted.
"This long-term agreement will further strengthen our position and commitment in the UK market."
NOS has 42 offshore vessels and is part of Northern Offshore Group (NOG).
"Our west coast offshore wind farms have a total capacity of more than 1.8 GW and are an important source of clean, renewable electricity," said Howard Shields, head of UK west operations at Orsted.
"A reliable CTV service is a vital tool in maintaining our excellent operational performance track record," he added.
Last January, NOG signed a deal with Japan's NYK Line to start a study into the provision of new CTVs in Japan.
The companies are teaming up on design, ownership and operation of CTVs, and will discuss further collaborations on overseas business.
