There's no real limit but you should use your best judgement. A family with a 9 year old joined our party and it was fine.
7 years old to participate with a parent or guardian as stated on their FAQ. For the record, they also have a statement saying that all ages are welcome. We visited with an eight year old. They enjoyed the activity, but, weren't able to solve any of the clues.
Not sure if it really has one, it puzzles,so might be over the head of young children
Thanks! Your answer is awaiting moderation.