Wade's contract with the Cavs is a reported one-year deal for the veteran's minimum - $2.3 million.
"There's no better place to be right now to continue to play and compete at the highest level," Wade posted in a tweet. "I look forward to reuniting and playing alongside my brother LeBron (James). We've already won two championships together and I hope we win a third."
According to ESPN's Adrian Wojnarowski, Wade was set to sign the contract Wednesday and participate in an evening practice with the team. The Cavs will cut rookie JaCorey Williams to make room for Wade, a source told Cleveland.com's Joe Vardon.