How old must you be to enter the attraction unaccompanied? All visitors under the age of 16 must be accompanied by an adult over the age of 18. Related articles Are there any restrictions for children at SEA LIFE Manchester? Do I have to pay for an under 2 ticket? Do you have toilets? How do I redeem a voucher at SEA Life Centre Manchester? What if I need to collect my tickets but I do not have the card I used to purchase?