Engineering Excellence
With Purpose
MDM designs and delivers the critical subsea infrastructure powering Europe's digital future, and connects communities along the way.
From Civil Engineering Beginnings to Subsea Infrastructure Leaders
Founded in 1990, MDM has grown from an Irish civil engineering consultancy into a globally recognised expert in subsea infrastructure. While we work extensively across Europe, our mission and impact extend far beyond it – delivering secure, high-speed connectivity that links continents, supports data centers, and connects communities.
We manage every step of the project lifecycle, from concept through operations, with a strong commitment to engineering excellence and long-term value.
Purpose-Driven Engineering
Why
We believe in securing the future of global digital infrastructure. Our work enables data centers, empowers regional communities, and supports digital sovereignty and innovation.
How
We deliver full lifecycle services with an integrated, in-house team along with our specialised, expert consultants. Our nimble and collaborative approach consistently meets aggressive project timelines while navigating complex stakeholder environments.
What
From major trans-oceanic systems like PISCES to regional Irish Sea deployments, MDM offers unmatched expertise in engineering, permitting, project development and operations and maintenance.
What Guides Us Every Day
Independent Excellence
Proudly privately owned, driven by purpose and precision
Technical Rigour
Engineering-first mindset in every detail
Human-Centered
Technology that improves lives
Resilient by design
Sustainable by nature
Partnership-Driven
Relationships that span decades
Meet the Team Powering Tomorrow’s Connections
Led by founders Tom and Jim McMahon, MDM is powered by a hands-on, multidisciplinary team of engineers and project managers. Our strength lies in deep local knowledge, trusted relationships, and a long-standing reputation for technical excellence and delivery.
Tom McMahon
Tom holds an honours degree in Civil Engineering and an MSc in Engineering Structures from Trinity College Dublin. He began his career at Mouchel Consulting Engineers and on the project management team for the Sizewell B Nuclear Power Station, before joining MDM. Since founding the company, he has led delivery of more than 30 major subsea infrastructure projects — including Ireland‑to‑UK, UK‑to‑Europe, and Ireland‑to‑Iceland cable systems — while also active as a sailor and board member of Irish Lights.
Jim McMahon
Jim is a co‑founder of MDM and brings over 25 years of telecoms and infrastructure experience across Ireland, the UK and Europe. He led the design and build of the first merchant subsea fibre‐optic cable between Ireland and the UK, and has since worked on landmark systems such as the UK‑Netherlands “Scylla” cable and the Ireland‑Iceland “IRIS” connection. He holds a degree in Quantity Surveying & Construction Economics from Trinity College Dublin.
Kevin Whyte
Kevin graduated (BEng, Civil Engineering) from the National University of Ireland, Galway in 2003 and is a member of the Institute of Engineers of Ireland and the Project Management Institute. Since joining MDM in 2017, he has led feasibility, route‑design, marine survey, procurement, permitting and construction operations across international subsea and offshore energy infrastructure projects.
Rory Ryan
Rory earned his BE and MSc from University College Dublin and is a Chartered Engineer. Since joining MDM in 2011, he has >15 years’ experience leading project planning, procurement and construction for major subsea telecoms including IRIS, Scylla and Rockabill. Most recently, Rory is leading the development of the PISCES Cable System.
Ed Siegle
Ed has over 25 years of experience in the telecoms industry, focused on the planning and commercialisation of many forms of digital infrastructure. Before joining MDM Ed worked for fibre operator Ogi, where he led the high-capacity wholesale business, and prior to that he worked as a Consulting Director for EMEA and North America for telecoms Consultancy Omdia, and Principal Consultant at Engineering firm Mott MacDonald, leading telecoms projects in the UK, Europe, Africa and South America.
Gearóid Walsh
Gearóid is a project engineer with MDM. He graduated from Trinity College Dublin with a Master’s in transportation engineering and a Bachelor’s in civil, structural and environmental engineering in 2021.
Since becoming part of the MDM team in 2025, he has been responsible for the preparation of feasibility studies, permitting documentation, technical drawings and engineering designs for both the terrestrial and subsea elements of several infrastructure projects.
Isobel O'Grady
Isobel joined the team in 2023 after earning a BSc in Business & Management and a Professional Diploma in HR from Technological University Dublin. She now supports business development efforts and handles technical administration across our subsea cable and infrastructure projects.
Ewan McMahon
Ewan is a dedicated engineer at MDM, holding a Master’s in Energy Systems Engineering and Bachelor’s in Mechanical Engineering from University College Dublin. Since joining the team, Ewan has been involved in many projects, including several terrestrial and subsea telecoms works, with particular focus on preliminary project study and post project operation & maintenance analysis.
Jack McMahon
Jack is a Junior Project Engineer at MDM. He graduated from Technological University Dublin in 2024 with a bachelor’s degree in Civil Engineering, followed by a master’s degree from the University of Southampton in 2025. Since joining the MDM team, he has supported the successful delivery of several ongoing subsea projects.
Jamie McMahon
Jamie is a Junior Engineer at MDM and a current master’s student at University College Dublin. He graduated with a BE in Mechanical Engineering and is completing a MSc in Mechanical Engineering with Business.
Since joining MDM, Jamie has been involved in a range of subsea telecommunications work, with a particular focus on preliminary project studies and post-project operations and maintenance.
Louise Cahill
Louise joins the team as an experienced Finance Manager with 30 years’ experience supporting operations through precise accounts, payroll and process driven financial management. A qualified Accountant Technician with IPass qualification, she also has a professional diploma in HR Management from the UCD Professional Academy.
What Sets MDM Apart
Clients choose MDM because we deliver results others can’t. With decades of experience, a hands-on team, and a proven process, we consistently outperform larger competitors while staying flexible, responsive, and transparent.
- 30+ years of end-to-end delivery
- Deep in-house engineering capabilities
- Market-leading project timelines
- Trusted by hyperscalers and governments
- Proven discretion and reliability
MDM by the Numbers
A track record that speaks for itself
subsea cable systems
delivered
coastal communities
years of operations and
engineering expertise
km of subsea cables