In a case governed by federal law, the arbitrator not the court decides whether the defendant has waived arbitration at least by acts other than participation in litigation. But under California law, the court decides issues of waiver. (CCP 1281.2(a).) In this case, despite a choice of FAA law in the arbitration clause, California law governed this issue because plaintiffs’ claims arose under California wage and hour statutes. Here, the employer waived arbitration by actively litigating the employees’ wage claims before the Labor Commissioner for three years and then in court for another year before moving to compel arbitration, attempting to remove the case to federal court and taking other steps inconsistent with arbitration during the year the case was pending in court. As in Fleming Distribution Co. v. Younan (2020) 49 Cal.App.5th 73, the employer’s delay in moving to compel arbitration waived the right to do so. Even though prejudice may not now be required to establish waiver of the right to arbitrate, the employees were prejudiced by the employer’s delay since they were forced to litigate for years to obtain their wages. Delay in payment of wages is prejudice.