The tidal site covers approximately 35 square kilometres, between half a kilometre and six kilometres offshore from Holy Island. Water depths average around 40 metres and reach 72 metres in the northwest corner. The strong tidal currents that make this site economically attractive are a function of the same geography that has made Anglesey treacherous for shipping for centuries - the Irish Sea funnels its tides past Holy Island in volumes that have killed shipping but can now drive turbines. The Crown Estate has leased the seabed for 45 years. The water column above belongs to a project being built in deliberately phased steps, with environmental monitoring at every stage so that the impact on guillemots, razorbills, and other Irish Sea wildlife can be measured against baselines collected before any devices were installed.

Before any turbine generates a kilowatt, the onshore infrastructure has to exist. Jones Brothers, a civil engineering firm from Ruthin, completed the initial onshore grid connection in June 2023, three months ahead of schedule. Mark Drakeford, then First Minister of Wales, formally opened the onshore substation in October 2023, calling Morlais 'a groundbreaking project and a key part of our transition to a low carbon economy'. In February 2025, the Welsh Government took an 8 million pound equity stake in the project, with the money going toward grid capacity improvements at Parc Cybi in Holyhead. In July 2025, work started on a 16 million pound grid upgrade project called Cydnerth - Welsh for resilience - which will scale the grid connection from 18 MW to the full 240 MW. The Cydnerth project will connect the Morlais substation at Ynys Lawd, near South Stack, to the National Grid at Parc Cybi via Jones Brothers' civil engineering.

Morlais is split into multiple berths leased to different tidal energy developers, each with their own turbine technology. Hydrowing, part of the Inyanga Marine Energy Group, plans an initial 10 MW phase using next-generation Tocardo T3 turbines on multi-rotor frames. The company has won Contracts for Difference in UK auction rounds AR5 and AR6 to deliver 20 MW total by 2027 or 2028. In May 2025, Hydrowing awarded the fabrication contract to Hutchinson Engineering in Cheshire, with final construction in Wales in early 2026. Spanish developer Magallanes Renovables secured separate CfDs in AR4 and AR5 for floating-platform turbines. Verdant Isles - a joint venture of Verdant Power from the United States and Duggan Energy from Ireland - won a CfD for 4.9 MW at berth BL3. In June 2024, Inyanga and Verdant Isles agreed to collaborate to unlock economies of scale.

RSPB Cymru raised concerns about the project's potential impacts on guillemots and razorbills, which nest in large numbers on the cliffs at South Stack just north of the Morlais site. The environmental impact assessment was extensive, with independent studies on construction, operation, and decommissioning. A monitoring buoy carrying cameras and other sensors was deployed in July 2023 as part of the Marine Characterisation Research Project. The Environmental Monitoring and Mitigation Plan was approved by Natural Resources Wales in September 2024. Other companies once interested in Morlais have stepped back: Nova Innovation and Sabella announced joint plans for 12 MW in January 2022 with no follow-up since; Orbital Marine Power announced floating 2 MW Orbital O2 turbines in 2018 with no further news; Minesto tested its tidal kite prototype in the Holyhead Deep just west of Morlais in 2018 and 2019 before withdrawing from Welsh waters in March 2022. The Morlais berth-by-berth model assumes that as some developers fall away, others will fill the gaps. The first devices, from one developer or another, are still expected in 2026.