Yoshi's Island (race course)

Yoshi's Island is a race course in the Mario Kart series that debuts in the fourth wave of the Booster Course Pass for Mario Kart 8 Deluxe. It is a course that takes place on the island it is named after, with its music theme being a remix of the athletic theme from Super Mario World 2: Yoshi's Island. It is the second course to be introduced to the Mario Kart series in the Booster Course Pass, after Sky-High Sundae. Unlike Sky-High Sundae, this course was not announced for Mario Kart Tour alongside its reveal, even though internal data points at it being developed as a new course of Mario Kart Tour.

Akin to other courses based on games outside of the Mario series, this course uses the logo for the series it is based on for its starting line, and the course itself is heavily inspired by the game it is based on, featuring obstacles like Stilt Guys and Huffin Puffins, and mechanics like Winged Clouds that can summon stretches of road when driven into. The layout of the course appears to reference all the world themes from Super Mario World 2: Yoshi's Island. Many cameos from the game appear in the background, including Incoming Chomps, Petal Guys, Goonies, an enormous Nep-Enut, and Yoshi's ally Poochy. Additionally, there is a Goal Ring near the finish line. Similarly to Hyrule Circuit, Animal Crossing, and Urchin Underpass, this course has unique coins—in this case, the coins have the same design and collection sound effect as in the Yoshi's Island series. Koopa Paratroopas and Sidesteppers also appear on the course.

Excluding courses announced simultaneously, this course and Piranha Plant Cove mark the shortest period of time between the announcement of two new courses for the Mario Kart series, with them being announced five days apart from each other.

Course layout
Racers begin at Yoshi's House in a field that resembles World 1 from Super Mario World 2: Yoshi's Island. Racers race along a slight serpentine path, avoiding Stilt Guys before diving into an underwater section. Surrounding the underwater section is a forest that resemble the basis' World 2 and World 3. This section ends with racers driving into a castle; the route after this point is unclear, though it appears that the castle leads into an underground section. Eventually, racers drive by pink mountains similar to the ones in World 4 before driving up an active volcano, like the one in World 6. A glider ramp then takes players up to the clouds, driving above snow-capped mountains similar to World 5, before taking another glider to the ground level where they can drive into a Winged Cloud to make a bridge appear. After reaching the ground (or the aforementioned bridge), they soon return to the finish line.