The 23-year-old moved to the Kassam Stadium on a short-term deal from New Zealand outfit Northland at the end of last year.
"I wanted to come and play and get some experience here, and so far it's gone pretty well for me," said Caprice.
"Every match you want to perform the best you can for yourself and your team. I just want to keep learning and improving.
"There's a relaxed environment at London Welsh - it's different to any club I've ever been at."
Caprice has had previous spells with Saracens and Biarritz.