Originally Posted by
closetasfan
Tokyo Disneyland - Disney Sea
Only because it is August. Unless the OP and his small child like standing in hour+ lines in humid 35C/95F weather.
The only way I'd consider Disney Sea at that time of year is if you're able to splurge for a Disney Resort Vacation Package and stay at the Mira Costa. Then the combination of proximity and VIP passes might make it worthwhile.