The 18 Scottish Citylink vehicles on Europe's most frequent service comprise Scotland’s largest fleet upgrade.
They will replace existing coaches on the round-the-clock 900 service, increasing seats by up to one third, with an extra 2,500 a day.
The move follows passenger numbers on the route, which operates up to every 15 minutes, increasing by 12 per cent over the last two years.
Other new features include extra legroom and luggage space, fold-down tables, reading lights, mobile device holders and USB chargers.
The Alexander Dennis Limited (ADL)-built Plaxton Panorama 79-seat vehicles are similar to those introduced by Scottish Citylink on its Glasgow to Edinburgh Airport service in November.
Transport secretary Michael Matheson, who launched the fleet at the Riverside Museum in Glasgow, said: “This is a welcome investment from Scottish Citylink and a fantastic upgrade for passengers on the 900 route between Glasgow and Edinburgh.
“To improve our air quality, reduce congestion and respond to the climate emergency, we need more people to choose to leave the car at home and to take more sustainable forms of public transport.
"The new amenities on this already award-winning intercity bus route will make that choice even easier."
'Fantastic travel experience'The service, launched 35 years ago, is operated for Scottish Citylink by Stagecoach West Scotland and Park's of Hamilton.
“This investment is further evidence of our belief in the future of coach travel in Scotland.
"Our coaches on this route cover over 2.5 million miles each year, and we are proud to be introducing these luxury high-specification coaches for our customers.”
ADL chief executive Colin Robertson said: “Our team has collaborated with Scottish Citylink, Stagecoach and Park's of Hamilton to deliver a fantastic travel experience that will set new standards.”