Plans include the launch of a new restaurant concept and refurbishment of the 148 rooms at the former Hilton Newport hotel.
The acquisition will bring Celtic Manor’s total room stock to almost 600 and safeguard over 100 staff jobs.
Matthew Barnby, Coldra Court hotel manager, said: “The Coldra Court is a four-star hotel in terms of facilities but we will run it with the same five-star service standards associated with the Celtic Manor Resort.”
Coldra Court features a swimming pool and health club, Seasons restaurant and 220-cover celebration suite.
It joins Celtic Manor’s growing portfolio, which includes the Manor House, the Newbridge on Usk and 10 Hunter Lodges.
The main Resort hotel - which sits in 2,000 acres of parkland - hosted The Ryder Cup in 2010.