Tokyo Disneyland

Hi Fred, the difference is the theme of the parks. Disneyland is the "regular" Disneyland you would find in the U.S. Disney Sea has more of a ocean/adventure  theme as you can guess from its name. So you'll find rides for Nemo or Ariel, Indiana Jones, etc. At Disney Sea, some drink booths sell alcohol whereas Disneyland doesn't sell any alcohol, so I think DisneySea would be more appropriate for adults.