The American and former world number two, currently ranked 86th, has been sidelined with injury since May and says he will not play on the relaunched tour until next year as he continues to recover from surgery in right knee.
The controversial tour, which is financed by Saudi Arabia's state investment fund PIF, is accused of being part of so-called sportswashing, a way for Saudi Arabia to use sports to wash its reputation when it comes to, for example, human rights.
Even the Swedish golf star Henrik Stenson has recently changed playing on the American PGA tour and the European tour to playing on the LIV tour.
Stenson has had to withstand criticism for his choice, which, among other things, cost him the captaincy of Europe's Ryder Cup team.
LIV Tour competitions differ from PGA and European Tour competitions in several ways, including the fact that players represent teams and not just compete individually.
The prize money is also clearly higher.
According to Watson, he is particularly attracted to the team aspect and plans to join the LIV tour as a non-playing team captain until he is ready to compete again.