UniSea was founded in 1974 to engage in the booming King Crab and Tanner Crab fisheries in the Dutch Harbor and Bering Sea areas of Alaska. Then known as Universal Seafoods, Ltd., the company converted a World War II Liberty ship into a shore-based seafood processing vessel, the Barge UniSea. The processing barge was towed to Alaska and arrived at dock in Dutch Harbor in July 1975. In October 1975 the Barge UniSea began processing.

In 1977 construction is completed on a cold storage and processing facility in Redmond, Washington. The plant had a floor area of 150,000 square feet with 27,000 square feet of processing area and 1.8 million cubit feet of cold storage space controlled to minus 15 degrees F. The plant is sited on 11 acres and included office space which served as company headquarters.

In December of the same year Universal bought the Vita Foods production facilities in Dutch Harbor, Alaska and crab processing area in the Bellingham Cold Storage complex. The Barge Vita located next to the Barge UniSea continued to process crab for Universal until it was sold for scrap in 1986.

The UniSea Inn hotel, restaurant, and lounge, is built overlooking what is now known as the Small Boat Harbor. 

In 1979 Universal completed an addition to the UniSea Cold Storage facility in Redmond, Washington, adding three shipping and receiving docs, and a fish processing area.

In 1985 Universal purchased the Pacific Pearl seafood processing facility in Dutch Harbor and converts the plant for the production of surimi. Surimi is a frozen fish protein manufactured from pollock, a white fleshed bottom fish which is used as the main ingredient in some processed food products such as imitation crab.

In the fall, the company adds a line of specialized processing equipment to produce Kanibo, or imitation crab, in the Redmond plant.

And, during 1985 Universal Seafoods, Ltd was renamed UniSea, Inc.

UniSea began processing pollock into surimi in 1986 at the converted  Pacific Pearl Seafoods plant in Dutch Harbor, now renamed Great Land Seafoods (GLS). UniSea was one of the early shoreside processing entrants into the Americanization of the Bering Sea groundfish fisheries. The plant began with a capacity of 150 metric tons per day of groundfish and marketed its surimi and fish meal products under the GLS brand. By 1990 the plant, generally known as G1, increased production capacity to 400 metric tons of round fish per day.

In 1989, UniSea began construction on the G2 Surimi plant and associated complex. These facilities included a new 15.6 megawatt powerhouse, refrigeration plant, cold storage, new bunkhouses, galley and recreation center, and new 800 metric ton per day fish meal plant. The new 1600 lineal feet heated dock for the fishing fleet is the longest continuous dock in Alaska. 

In December 1990 Redmond administrative employees moved into the new Corporate Office located next to the Redmond Plant.

In September of 1990, UniSea began processing operations in the new G2 facility. Combined, the G1 and G2 plants process up to 1200 metric tons of pollock per day, making UniSea one of the largest producers of surimi in the world. The byproduct of this production is processed into fish meal, bone meal, and fish oil, making G2 one of the most efficient operations of its type.

In February 1991, Dutch Harbor administrative employees moved into the new administrative offices located above the G2 production facility. In March a new cod line was installed in the G1 operation and a crab line was added in May. In January 1992 UniSea's new Dutch Harbor Galley was completed.

The new Grand Aleutian Hotel opened in May 1993 with 110 guest rooms and suites, two restaurants, a gift shop, and 2800 square feet of meeting space. 

The Barge UniSea was relocated to St. Paul in 1993 where it continued to process crab until it was sold for scrap and towed to China in 2000.