Swansea, Ospreys and ex-Wales Under-21 scrum-half Richie Rees has joined London Irish on a one-year contract.
Rees says his chances at the Ospreys were limited
The 23-year-old, who has the option of a further 12 months at the Exiles, says his regional chances have been limited.
"My ambition is to play for Wales and I don't think playing in England's top competition will do me any harm," Rees told the South Wales Evening Post.
Swansea have recruited ex-Wales Under-21 tight-head prop Martin Jones, 26, from Cardiff Blues.
Also moving to St Helen's are hooker Ashley James (Llanelli), back-rower Marc Popham, centre Richard Payne and full-back Ricky Williams (all Newport).
Popham is the brother of Wales and Llanelli Scarlets number eight Alix.
I'm a young player and if I'm to progress I need to be playing at a high level regularly
The All Whites have released Nick Kelly (work commitments), Darren Davies (injury) and Andrew Clatworthy, who could be set to join Llanelli, while Luke Richards is in talks with Maesteg.
Another former Wales Under-21 scrum-half, Rhodri Wells, announced earlier this year that he is leaving St Helen's for the Cornish Pirates.
New Zealander Jason Spice has been first-choice scrum-half at the Ospreys for the past two years, and the region have recruited fellow Kiwi Justin Marshall for next season.
"The Ospreys? There just weren't enough opportunities for me there," said Rees, who has played for the region 11 times in the last two seasons.
"I'm a young player and if I'm to progress I need to be playing at a high level regularly rather than once in a while.
"I am excited about the move, London Irish are a club who are going places and this is a great opportunity for me.
"I had a chat with their coach Brian Smith and he told me they like to play a running game, which suits my style of rugby.
"There is also the bonus that they are in the Heineken Cup. I have played in that competition with the Ospreys over the past two seasons and it is something all players want to be a part of."