Legal Question in Family Law in California

Yes, but if the other spouse then files within six months, jurisdiction will still be in California, and the California court will look with significant disfavor on the spouse who took the children out of state without taking legal steps. If there is a compelling reason why the spouse had to leave, it may be excused, but generally the courts are not at all happy when a parent takes the children out of state without going through a proper custody process. So even though it is not illegal, it is a very bad idea to take children out of state without going to court first.