"We have been monitoring Kees's performances this season in the French Championship and have been very impressed," said Scarlets chief executive Stuart Gallacher.
"We have been hugely impressed by Kees. His physical condition is terrific and he proved to us he still has the motivation to play at the top level in European rugby.
"Along with Simon Maling and David Lyons he will bring extra physicality and power to our squad and he will be arriving with us in Llanelli in late June."
Auckland man Meeuws played for provinces Otago and Auckland in New Zealand, and for the Highlanders and Blues in the Super 12.
He moved to Castres in 2004, left for Agen for the 2006/7 season, then returned to Castres last season.
"Kees's record and pedigree as an All Black coupled with his desire to achieve further success makes him a great signing for the Scarlets," said new coach Nigel Davies.
"He is a proven leader whose experience will be vital next season."
Bookmark with:
What are these?