The vessels are all due to enter dry dock in Hamburg in November and December in preparation for the forthcoming winter cruise season.
Work has started with 804-passenger Black Watch ahead of a 14-night mystery cruise departing from Tilbury on November 15. An additional 27 balcony cabins are being built as part of the revamp.
The 929-passenger Braemar will arrive in Hamburg on November 12 for work prior to a three-night cruise to France from Southampton on November 20.
Balmoral’s dry dock work starts on December 9 with the 1,350-passenger ship leaving the shipyard for a two-night pre-Christmas sailing from Southampton on December 19.
The line’s managing director, Mike Rodwell, said: “We experience extremely high demand for balcony cabins across our fleet, and in particular on board the smaller-sized Black Watch, and our new balcony terrace cabins are an innovative response to this.
“We are also looking forward to being able to give guests the experience of fine coffee and chocolates on board Balmoral and Braemar, as they have already been enjoying on Boudicca and Black Watch.
“Fred Olsen Cruise Lines is pleased to be returning to Blohm+Voss for this important work. Balmoral and Braemar are both well-known to the Hamburg shipyard, as they both underwent mid-section extensions in 2007 and 2008 respectively.”