Neither of the players qualified in any of the categories used to determine invitations for the Masters, but have established themselves as two of the top players in Asia.
This will be the fifth straight Masters for Ishikawa, who has missed the cut in three of his four appearances.
Wiratchant was the leading money winner last year on the Asian Tour and is also the all-time leader in wins on that circuit. He will be playing in the Masters for the first time.
"We historically bring together a collection of the world's top players and this year is no different," Payne said. "The Masters has long established a tradition of supporting the global game and we were excited to extend invitations to Thaworn Wiratchant and Ryo Ishikawa, who we hope will provide added interest and enthusiasm for golf in Asia through their participation in the tournament."
The special invitations increase this year's Masters field to 85 players. That number could grow during the next three months if any players not otherwise eligible should win a PGA Tour event or if they move into the Top 50 in the world rankings.