The British-based Proteam announced its provisional six-man roster for the race on Tuesday.
Brits Thomas, Swift and Dowsett join compatriot Peter Kennaugh and Australians Michael Rogers and Mathew Hayman in the eight-day, nine-stage event.
“This is a strong and exciting team for the Tour of Britain,” said Sky principal David Brailsford.
“After a hugely successful season on the roads of Europe and beyond, it is really exciting to be racing in front of our home fans and we will be looking to repay the great support they have given the team all year.”
Thomas spent most of the first week of the Tour de France in the white jersey of best young rider, and must rank as one of the favourites for the overall win in the Tour of Britain. Thomas won the Bayern Rundfahrt stage race in May.
Swift is one of the most successful British riders this season, having scored stage wins in Tour Down Under, Vuelta a Castilla y Leon, Tour de Romandie and Tour of California. He will be in teh hunt for sprint stage wins.
Dowsett took his first professional victory last week when he won the final stage of the Tour du Poitou-Charentes in France. The Essex man will be looking to win the short time trial stage on the final day in London.
Kennaugh has had a strong season, coming third in the Route du Sud and placing fifth in the Tour of Poland.
Former time trial World Champion Michael Rogers continues his comeback after a long illness that blighted his early season. And 2006 Commonwealth Games road race champion Mat Hayman will provide solid support for the team.
Geraint Thomas predicts a ‘great week of racing’, saying “The Tour of Britain is a great race and this will be my sixth appearance. It is always exciting to ride in front of our home fans. The support we have had on the road all year has been amazing and has played a big part in the success we have achieved as a team.”
Sky’s Chris Froome and Bradley Wiggins current lie first and third overall in the Vuelta a Espana, which finishes on the day that the Tour of Britain starts.
The 2011 Tour of Britain starts on Sunday September 11 in Peebles, Scotland, and finishes in Westminster, London, on Sunday September 18.