Celtic Sub Sea - About us

About Us

Celtic Sub Sea is a highly experienced commercial diving services firm that operates throughout the offshore and inland domestic US market. Additionally, we consider international projects on an individual basis. At the core of our competitive advantages lie our highly-qualified personnel. Our trusted professional networks and recruitment resources grant us access to the some of the most competent commercial diving professionals in the world. Our employees come from a wide array of backgrounds including former United States Navy EOD, SEAL, and Salvage Divers; former Municipal Police and Port security personnel; and Gulf of Mexico, North Sea, Middle Eastern, and Asia Pacific Oil field divers.

Additionally, the Celtic Sub Sea Executive Management team has a cumulative 40+ years’ experience in Commercial Diving, Offshore and Inland Construction, Civil and Structural Engineering, Project Management, and Consulting disciplines. This has assisted Celtic Sub Sea in becoming one of the most highly qualified commercial diving firms in the world. Our quality is unsurpassed, and our attention to detail meticulous. Diving is our passion. Safety is our job.



“Celtic Sub-Sea Construction Services’ mission is to be the industry leader in commercial diving service- offerings by maintaining a never-ending commitment to client and personnel relationships; accented by unsurpassed safety standards, highest quality deliverables, and the most cost-effective business processes in the commercial diving industry.”


Celtic Sub Sea
Executive Management
Thomas M. Fennesy (CEO)
Kevin F. Scallan PhD (COO)
Michael A. Fennesy (CSO)
Kenneth Fennesy (SME)
Jeff Bonifas (Ops Mngr.)

Thomas M. Fennesy MBS (CEO)

Thomas M. Fennesy MBS comes to Celtic Sub Sea from Accenture, where he previously worked as a Systems Integration and Technology Management Consultant. During his time with Accenture, Thomas consulted on many different projects for multibillion dollar clients in the Financial Services and Resources Sectors. Additionally, Mr. Fennesy’s previous experience includes three years as acting CFO for a commercial diving firm located in Long Beach California and the Gulf of Mexico. Furthermore, Mr. Fennesy is well versed in Finance, Sales & Marketing, Information Technology, Management Consulting, and overall Operational strategy. Mr. Fennesy is a 2006 graduate of Vanguard University of Southern California where he excelled in his discipline and went on to finish top of his class with a BA in International Business and Cultural Anthropology. In 2007, he completed a Masters Degree with honors in International Business (MBS) at The University College Dublin’s Michael Smurfit Graduate School of Business, Ireland’s leading business school. Mr. Fennesy’s current specializations include the Oil & Natural Gas, Renewable Energy, Information Technology, and Financial Services sectors.