We report the design and performance of an advanced macroalgae cultivation system for offshore and exposed ocean environments. The field test was completed in the Atlantic Ocean in 2022 off the coast of Maine, USA. The project is funded by the US Department of Energy’s ARPA-E program to develop technologies that can enable large-scale macroalgae cultivation in deep water. Multiple new technologies were deployed in the field test, including new structural materials, components, and robotic anchoring with diverse applications in commercial offshore infrastructure. With two seasons of field tests completed, project team members are using collected data to evaluate the cultivation structure and component technology performance, improve upon those designs and to better inform the concept’s economic feasibility. The desired scales of production, harsh offshore environment, and low-cost requirements for offshore macroalgae aquaculture present a challenging engineering design problem. As the technology development effort has unfolded, we have identified routes towards an economically feasible system by integrating: synergies between infrastructural components, scaling efficiencies, structural resilience in overlapping modularity, and strategic agronomic processes. Our system sets the typical hectare scale longline farm within the context of massive (square kilometers scale) arrays of semi-independent farm “modules” supported by a lattice of novel multi-line moorings capable of increasing structural efficiency and resilience through distributed accommodation of hydrodynamic loads. ROVs designed to install the anchors enable low-cost deep-water deployments. Wave actuated tethered hydrofoil upwellers integrated into the mooring system harness ambient renewable wave energy to elevate deep cold nutrient rich seawater enabling conditions capable of extending temperate macroalgae growth seasons. Fiberglass rods replace conventional ropes as mooring lines and growth substrate to reduce the risk of marine mammal entanglement (a major barrier to permitting in US waters). Through ongoing validation efforts: numerical modelling, component testing, and pilot scale deployments, we will demonstrate how our systems and component technologies could support industrial scale macroalgae cultivation in offshore waters.