If I buy a Combo Ticket, do I have to visit SEA LIFE on the same day?

No, the date and timeslot you select is for LEGOLAND Discovery Center, but you're welcome to visit SEA LIFE any time that day or within the next 14 days. The average family spends 60-90 minutes at SEA LIFE and 2-3 hours at LEGOLAND Discovery Center. Please see each attraction's website for complete hours of operation.