Swindon midfielder Louis Thompson has agreed a move to Norwich, while Southampton defender Jack Stephens has joined the Robins on loan until the end of January.
Thompson moves to the Championship side for an undisclosed fee, but has been immediately loaned him back for the rest of the season.
The 19-year-old midfielder has signed a three-year deal at Carrow Road with an option for a further 12 months.
Thompson told the official Norwich website: "I'm extremely proud. To come to a club of Norwich City's stature is a fantastic achievement for me. I'm really looking forward to the challenge of coming here after my loan finishes at Swindon.
"It's a massive club with a huge fan base, there's not a single negative thing to say about them. Hopefully they can do well this year and challenge for a Premier League place."
Centre-back Stephens, meanwhile, returns to the County Ground after making 10 appearances during a loan spell in Wiltshire last term.