Byrne joins Dave Stringer's side ahead of their opening pre-season friendly against Paget Rangers on Saturday.
The Royals' new signing played for fellow Pitching In NPL Midlands Division side Boldmere St Michaels, making 42 appearances in all competitions during the 2022/23 campaign.
His former club finished ninth last season, four places and 17 points above Sutton Coldfield.
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