“The way the manager wants to play, the way he was when I spoke to him, he was just full of so much enthusiasm. I’d never met him before but he made me feel about eight feet tall, which is just what you want.”
Ramsdale, capped five times for England, was selected for Gareth Southgate’s Euro 2024 squad.
He made 89 appearances for Arsenal after a £26m move to the Emirates from Sheffield United in 2021.
“Aaron is a real statement signing for us,” said Saints boss Russell Martin.