The voyages will take place on 2 August and 9 August after the original four July sailings sold out earlier this week.

The eight-day itinerary departs from either Edinburgh or Greenock and has a port stop and excursion included every day. 

Calls include Aberdeen, Inverness, Orkney, Oban, the Outer Hebrides and Belfast. Tours include trips to Loch Ness, Balmoral Castle, the Titanic Visitor Centre, the Callanish Standing Stones, and the Neolithic Ring of Brodgar henge and stone circle.

Sailings will be on the new-to-brand 158-guest MS Seaventure, which was refurbished in 2019. Riviera Travel said the expedition-ready ship was “the only one of its size to cruise the British Isles, meaning it can dock at and explore smaller harbours”.

Seaventure has 82 sea-view cabins, an onboard fitness suite, sauna, heated saltwater pool, expedition theatre and library.

The sailings mark the first time Riviera has offered UK-specific voyages. Prices start from £1,999pp, based on two sharing a cabin, including full board, tours, shore visits and all port taxes. A limited number of cabins are also available for sole occupancy without a supplement.

Head of cruise and worldwide product Katja Hildebrandt said: "We’re thrilled with the demand we have seen from the trade for our highlands and islands cruise, so are delighted to be able to announce these two additional sailings to everyone still looking to book up. 

“The itinerary will offer a fascinating insight into the culture and heritage that is right on our doorstep. The fact our ship can explore ports inaccessible to larger vessels will only add to the authenticity of the trip."