Best UK seaside place for toddler

[Littlepip02]

Hi everyone

Wanting to take my little boy on a break in the UK this year, not brave enough to do a flight with him yet lol. Any recommendations on where would be good? He will be around 20 months old when I want to go.
Any seaside locations/holiday sites welcome we will be going outside of the school holidays

Would people say Isle of Wight or Great Yarmouth for three days with a 21 month old? We’re in London so not too different distance wise.