Hotel Delfino

The Hotel Delfino is a luxurious hotel resort located in Sirena Beach, the sixth world of Super Mario Sunshine. The hotel is run by an extremely wealthy Pianta. Outside the hotel the sun is always setting. Inside is a maze of rooms, air vents, and a large casino. The Pink Boos make their first appearance here.

At first it completely disappears under electrified goop after Phantamanta attacks Sirena Beach. After Mario defeats it, the hotel rises from the goop. In the second through fifth chapters the hotel is infested by Boos, though most of them disappear when King Boo is defeated.

Casino
The casino is a sub-level of Hotel Delfino (which is itself a sub-level of Sirena Beach) in Super Mario Sunshine. Here Mario has to fight King Boo. It also includes two jumbo slot machines in which Mario can win coins or produce a Boo by spraying it with water. There are other, smaller slot machines that Mario can Ground Pound to get more coins. There is also a tile set Mario needs to match in order to access a secret stage in Episode 4. A giant roulette wheel is in the center and in Episode 5, Mario has to Ground Pound a special purple tile to reach the fight with King Boo in the hotel's basement. Mario can only enter the Casino in Episodes 4 and 5 and once he does, he can't return to the rest of the hotel without quitting and coming back the level.

Music
The music of Hotel Delfino features rhythm ukulele, electric bass, and various percussion instruments, including bongos, congas, güiro, marimba, vibraphone and wooden wind chimes throughout. A theremin-like synthesizer comes in and out with the melody. The casino's music is completely different; rather, it implements saxophone, honky-tonk piano, electronic organ, upright bass (pizzicato), whistling, and a drum set. The same casino music can be heard in Luigi's mini-games in Super Mario 64 DS and New Super Mario Bros., but without the ones as mentioned above.