Microsoft has filed to potentially develop three subsea cables connecting Ireland to the UK.

First reported by Roderick Beck’s subsea cables and Internet infrastructure blog [1–2], Microsoft’s Irish unit has filed three application forms with the Irish Maritime Area Regulatory Authority that detail plans for three cables connecting Ireland to Wales in the UK: Tuskar, SOBR1, and SOBR2.

The three applications were filed last year but not widely reported before now.

Tuskar would run from Kilmore Quay in County Wexford to Newgale on the Pembrokeshire Coast of Wales. The application is for a marine survey along proposed routes through the Celtic Sea and St Georges Channel.

SOBR1 is set to run from Dublin Bay across the Irish Sea to make landfall at Anglesey on the North West coast of Wales.

SOBR2 would run from Portmarnock and/or Malahide outside Dublin in Dublin County across the Irish Sea to Abergele on the North coast of Wales.

Most of Ireland’s subsea cables land around Dublin on the east coast or on the west coast around Mayo or Galway.

Microsoft has more than a dozen data centers in operation or development at multiple sites around Dublin. It is also planning to develop a campus southwest of Dublin in Naas, County Kildare.

The company is also present in Wales, reportedly leasing capacity at Vantage's campus in Newport and known to be developing its own campus nearby. Vantage is developing another campus in Bridgend, new operator Latos is planning a 90MW data center in Cardiff and a 350MW campus has been proposed in Anglesey.

Microsoft is an investor or leasing capacity on several cables, including those landing in Ireland and the UK. According to Telegeography, the company is a part owner or major capacity buyer on the AEC-1, Amitie, Exa Express, Marea, New Cross Pacific, and SeaMeWe-6 cables.

Launched in 2015 as the Hibernia Express (and later GTT Express), the 53Tbps Exa Express system links Ireland to the UK and Canada, landing in Brean in the UK and Halifax across the Atlantic. Exa’s landing point in Cork is at the Cork Internet eXchange/CloudCIX on the Hollyhill Industrial Estate in Cork.

Aqua Comm’s AEC-1, launched in 2016, links Ireland to the US, landing in Killala in County Mayo and Shirley, New York. Aqua was acquired by Exa earlier this month.

Amitie, launched in 2023 by a consortium of Microsoft, Meta, Orange, Vodafone, and Aqua, doesn’t land in Ireland but does connect Bude in the UK to France and the US.

In response to an Irish government telecoms consultation on subsea connectivity last year, Microsoft said permit applications had been submitted for the Tuskar, Beaufort, and SOBR1/2 subsea cable systems.

“In the future, Microsoft may need to obtain capacity on other systems landing in Ireland built by others not only for capacity, but also for diversity and redundancy for greater resiliency,” the company said.

Amazon, which like Microsoft has a major data center presence in Ireland, last year also filed to develop its own subsea cable linking Ireland to the US.

Amazon is also working with Vodafone on the Beaufort cable, which is set to link Ireland to the UK. Due to land at the former ESAT 1 landing station at Kilmore Quay in Wexford on the Irish side, it will also land in Bude in England and Port Eynon in Wales on the UK side. The cable was originally expected to be ready for service in 2024. Microsoft has not previously been linked to Beaufort.

DCD has reached out to Microsoft for more information.