The 20-year-old, a product of the Camrose club's youth system, impressed during a loan spell at Hendon last season, before starring for Jason Bristow's team towards the end of the campaign.
He had been training with Wimbledon, whose goalkeeping coach is former Town shot-stopper Ashley Bayes, last season. Wombles manager Neal Ardley was clearly impressed by what he saw from the former Cranbourne Buisiness and Enterprise College pupil.
“Joe came in and played Under-21 games for us last season and he knows Ashley Bayes, who was at Basingstoke previously,” Ardley said. "He was outstanding in a match for the Under-21s against Charlton last season and it was one of the best goalkeeping performances that I had seen.
"He came in and trained regularly with us last season and looked like a first-team goalkeeper. We are out there recruiting and we felt that if we did not get Joe and start trying to develop him then someone else would.
"We are delighted that he has come in to be a part of our Under-21 set-up for next season."
The loss of McDonnell, for whom Town will be due a fee, leaves Bristow without a goalkeeper with only four days until the club open their pre-season schedule at Winchester City.
However, the Basingstoke boss has indicated that he is close to signing a new number one.