Hampshire's Dominic Cork lifts the FP t20 trophy at The Rose Bowl in August
Hampshire and Somerset have accepted an invitation from the West Indies Cricket Board to play in the Caribbean T20 in January next year.
Hampshire beat Somerset in the final of the Friends Provident t20 in August.
The counties were unable to take their places in the Champions League Twenty20 in South Africa because it clashed with the end of the English season.
The early rounds of the Caribbean tournament will take place in Antigua, with Barbados hosting the final stages.
"The Caribbean T20 rewards Hampshire and Somerset for their hard work throughout the 2010 Friends Provident t20 campaign," said England and Wales Cricket Board director of marketing and communications Steve Elworthy.
"It provides an excellent opportunity for both teams to experience playing in a different environment and test themselves against strong opposition."
Somerset will be able to call on the vast majority of their squad, the notable absentee being captain Marcus Trescothick.
Asked whether the former England opener would be making the trip, chief executive Richard Gould told BBC Somerset: "Marcus won't be going. That's definite.
"The likes of Peter Trego will be brought back from Melbourne, Nick Compton from Zimbabwe, plus we've got a few deployed with England teams.
"Plus we've got the likes of Gemaal Hussain and Steve Kirby. It'll be a great opportunity for them to start gelling into what we do as a squad."
Hampshire became the first side to win the English domestic Twenty20 title on their own ground when they beat Somerset by virtue of losing fewer wickets at The Rose Bowl in August.
Now both sides will join Barbados, Jamaica, Leeward Islands, Trinidad & Tobago, Windward Islands, Combined Campuses & Colleges and defending champions Guyana in the Caribbean for the tournament which runs from 10-23 January.
"It will be tough for the English sides simply because of the time," said Hampshire coach Giles White. "We only have two days to prepare when we are out there.
"All things considered, we'll be up against it early on but hopefully we'll put on a good performance and build from there. A good start is key.
"The biggest challenge is getting the players who have not played outdoors in a while up to speed. But the team are enthusiastic and we will go out there with an open mind."
The deal between the ECB and WICB has echoes of the Stanford Super Series, which took place in 2008.
Organised by Sir Allen Stanford, England and then domestic T20 champions Middlesex were invited to play in a series of matches against the Stanford Superstars and the Stanford 20/20 winners Trinidad and Tobago.
Bookmark with:
What are these?