How do I unlock the hidden characters for Big Beach Sports?

There are three hidden characters waiting to be unlocked in Big Beach Sports.

To unlock them enter the following on the D-Pad whilst on the welcome screen. This must be done before pressing A to proceed to the main menu.

Shark
Left, Right, Left, Right, Up, Up, Up, Up, Up

Bee
Right, Right, Up, Up, Down, Down, Down, Down

Pirate
Left, Left, Left, Left, Left, Left, Right, Right