In Super Mario Sunshine, what is the name of the first proper level?

In Super Mario Sunshine, the first proper level is Bianco Hills.

Bianco Hills is the first dedicated course Mario enters after the opening events on Isle Delfino. Mario reaches it through the Rainbow M-shaped portal in Delfino Plaza after chasing Shadow Mario. The course is a pastoral hillside region with villas, windmills, flower gardens, and a lake, giving the game an immediate contrast with the busy plaza and airport introduction.

Its opening episode, “Road to the Big Windmill,” teaches players how to use F.L.U.D.D. to clean goop, defeat enemies, and navigate the terrain. Later episodes introduce Petey Piranha, secret platforming areas, red-coin challenges, and Shadow Mario encounters. Bianco Hills therefore serves as both the first major course and a tutorial for Sunshine’s water-based movement.

Delfino Airstrip and Delfino Plaza appear before it, but they function as introductory or hub areas rather than the first proper course. Ricco Harbor, Gelato Beach, and Pinna Park are unlocked later.