Four-time Paralympic gold medallist Jason Smyth has left the training group in Florida which included Tyson Gay.
Former world 100m champion Gay tested positive for a banned steroid in June but Smyth says his decision to relocate to London is unrelated to that issue.
Northern Irishman Smyth is now being coached by 1988 Olympic 4x100m relay silver medallist Clarence Callender at London's Lee Valley Athletics Centre.
"I felt that I needed to be somewhere all year round," Smyth told BBC Sport.
"This year, I especially felt that living in the States for so long and trying to come back home in the summer didn't work.
"I felt I needed to be somewhere where I can be comfortable where I am and where I know my surroundings."