The Donghae 1 wind farm would be built near government-owned KNOC's natural gas field off of Ulsan City on South Korea's south-east coast.
Pending the results of a feasibility study to de-risk the project, construction could start in 2022 ahead of commissioning in 2024, Equinor stated.
The project partners will consider installing the 200MW wind farm's substation on the existing gas platform at the Donghae site, 58km from the shore.
KNOC and Equinor had signed a memorandum of understanding (MoU) to investigate the potential for floating offshore wind development in South Korea in February 2019.
The Norwegian company operates the 30MW Hywind Scotland project, the world’s first commercial floating offshore wind farm, commissioned in 2017.
It is considering supplying platforms at two oil and gas fields with power from an 88MW floating array off the coast of Norway.
Equinor also operates wind farms with fixed-bottom foundations off the coast of the UK, and is developing offshore projects in Germany, Poland, and the US. Equinor said Asia is a "key future market".
South Korea has 1,136MW of installed wind power capacity, according to Windpower Intelligence, the research and data division of Windpower Monthly. Offshore wind accounts for 38MW of this total.
But more offshore wind capacity is in the pipeline.
Last month, Macquarie's Green Investment Group deployed a floating lidar at the proposed site of a 1.4GW wind farm off Ulsan. It also signed an MoU with Korean fund manager Energy Infra Asset Management to help develop the three-phase project.
The South Korean government plans to increase its renewable energy capacity from just over 11GW today to 58.5GW by 2030, the ministry of trade, industry and energy announced in December 2017.
Wood Mackenzie Power & Renewables (WMPR) expects South Korea’s offshore wind capacity to reach 6.4GW by 2030. By then, offshore wind will make up about 6% of the country’s power mix, the analysts added.
Reacting to the announcement of the Donghae consortium, senior analyst at WMPR, Robert Liew, said: "This announcement further supports the growth of offshore wind in Asia Pacific.
"If completed by 2024, the 200MW Donghae project will be the first and largest utility scale floating offshore wind project in the region."
Liew added: "It will also signal to the market, the commercial viability of such projects, and boost the growth of offshore wind as floating offshore wind enables access to more offshore sites, and opens up potential new opportunities in other regional markets outside East Asia."