So if I buy one adult and get one kid free right now to use in January. Once I go the park in January will I have any issues?

No I'm not sure if you will, because if you use it in January it can be used all January of next year.

Hello Mari Rosales, If you are able to purchase the tickets for January through the Kids Go Free promo links, then your tickets will be set for the day in January that you choose.

Mari, I can't make any promises, but I've never had a problem at Legoland.

You have to pay for the kid's