SNES Rainbow Road

The original Rainbow Road debuted in Super Mario Kart, as the last course of the Special Cup, starting the Mario Kart series tradition of having Rainbow Road as the last course of the final cup. It is the shortest Rainbow Road to date, and it is the most common retro track in the series, having appeared six times in different games, more than any other Mario Kart track.

This course is unique in Super Mario Kart in the fact that it is the only track in the game that is not numbered compared to the others, and thus it is the game's only unique track. It is the only track in the Special Cup with normal traction, but lacks rails entirely and has only 90-degree turns. Rainbow-colored tiles and a few jumping bumps cover the track's surface, and the yellow tiles conceal Coins. This course features Star Thwomps which can wipe out a racer by touch, unlike regular Thwomps, as well as by crushing, unless the racer uses a Super Star or a Boo.

Course layout
The track begins with racers taking a turn to the right, where they will find ? Panels to gather items. There are some Jumps, followed by four Thwomps. After this, racers turn to the right again where they can collect some coins, followed by another turn to the right, where there is once again a path with jumping bumps with an incoming turn that might cause racers to fall. After this turn, the track gets narrower and follows a long path where more coins and Thwomps are found along the way with another turn awaiting the player. It is here where the track gets even more narrow increasing the risk of falling. Before the final turn, the track splits into two roads; the left side contains coins while the right side has two ? Panels, both have a pair of Thwomps near the part where these roads merge. Alternatively, there are two jumping bumps in the middle gap; if any racers use a Mushroom while they are heading for them, they can jump over the gap for a significant shortcut. After the final turn, before the finish line, there is another quartet of Thwomps, but this time there is no space between them to pass, with players only being able to pass them by driving on the side or when the Thwomps are rising.

Mario Kart: Super Circuit
Rainbow Road reappeared in Mario Kart: Super Circuit, as the last track of the Extra Special Cup. The background is from that game's own Rainbow Road, but with only the sparkles, foreground clouds, and moon appearing; like that track, this one is also translucent. The Thwomps and jumping bumps are removed. The coins' placement is also changed so that all coins are on blue tiles, making it much easier for players to collect them.

Mario Kart 7
Rainbow Road returns again as the last course of the Lightning Cup in Mario Kart 7, being the first Rainbow Road to reappear as a Retro track in another Mario Kart (besides its reappearance in Mario Kart: Super Circuit).

Even though this track is short, and is one of the shortest tracks in the game, there are only three laps instead of five. The course uses a similar background to that of DS Waluigi Pinball.

Unlike previous incarnations, this new version has the characteristic "glistening" sound effect when drifting on it, a common feature of all Rainbow Roads starting from the GCN rendition.

Unlike in Mario Kart: Super Circuit, the Thwomps (now with their New Super Mario Bros. Wii appearance) return. They are now larger (which reduces their number in the track, from sixteen to seven), and now form ripples on the track upon impact, which the player can trick off of. Also, howling noises can be heard near the Super Thwomps.

The tiles' colors are similar to those of Rainbow Road from Mario Kart: Super Circuit, with pink replacing the red tiles and cyan replacing the turquoise tiles. In first-person view, the player can see through the breaks in the tiles. The widest part of the gap in the forked road is two tiles shorter, but the gap itself is also seven tiles shorter, making the shortcut easier to use. Also, the section of tiles before the fork (from the orange tiles on the narrow part of the straight after turn 7 to the purple tiles before the gap) is wider: the first orange, blue, yellow, and last purple tile rows before the gap are now two tiles wider. The finish line is also two tiles long, removing the red tiles that used to be in front of it.

Ramps replace the yellow bumps, though the first two bumps were removed entirely, the last pair at the fork is now a single taller ramp in front of the gap, and a ramp was added on the inside of the second U-turn, adding a new shortcut (requiring a Mushroom or Mini-Turbo to get across); the ramps are only two tiles wide, rather than three, like the bumps.

Like most other SNES and GBA Retro courses, a starting banner stylized after the Mario Kart 64 starting banners is added in this course.

Aside from enhanced percussion, the music sounds the way it does in the SNES version.

Mario Kart 8 / Mario Kart 8 Deluxe
Rainbow Road returns for the third time in the Legend of Zelda × Mario Kart 8 DLC Pack of Mario Kart 8 and in the base game of Mario Kart 8 Deluxe, appearing as the second course in the Triforce Cup. As a result, for the first time, a Rainbow Road course is not the last track in a cup.

The track's layout is similar to its appearance in Mario Kart 7. The tiles revert to their original colors, though their color pattern is reversed, and they are now flashing LED lights, like on N64 Rainbow Road. There are now eight different colors of tiles, instead of seven from its previous appearances (adding cyan between turquoise and blue), and the tiles the Thwomps land on are now white. The course itself is also larger, wider and banked (namely, the inclined third U-turn). Tiles at the edges of the track now have borders on the outer edges. The forked road is also altered further, with the narrow part of the hole's end filled in, and the ramp in front reverted to the original bumps' height and position. The music is also deeper-pitched and remixed, as with the other retro courses in this game.

The Thwomps work as they do in Mario Kart 7, but they now have sparkles, a mosaic-like appearance, horizontal rainbow lines running from bottom to top of them, and the species' Super Mario Galaxy appearance, like the other Thwomps in Mario Kart 7 and Mario Kart 8, rather than their spiked New Super Mario Bros. Wii design in Mario Kart 7. Additionally, all of the Thwomps are bigger except the last two. Unlike before, when they start to crash down, they will create rainbow waves above them. Also, when they shake before falling, and the moment they land, they make metallic glistening sounds. The waves on the track they create are now bigger, move more quickly, and disappear faster than in Mario Kart 7, making tricks more difficult to perform.

The course now takes place in a cloudy night sky with the moon visible, just like in Super Circuit, but it now has color-changing hills that stick above them. Various Toad Houses litter the landscape below the course, which in itself is similar to SNES Donut Plains 3. The starting banner is now redesigned, with colored blocks with a Star on top of it; the banner also stands on two walled areas, now making the start the only walled part of the course. Also, when a player approaches a turn, two green arrow holograms will appear behind the turn, and indicate in which direction the player must drive (similar to Super Circuit's Nitro courses). Once the player has made the turn, the arrows will disappear.

Staff ghost
The staff ghost for this track is Cat Peach on the Cat Cruiser, with a time of 1:46.599. In Mario Kart 8 Deluxe 200cc, the staff ghost is Tanooki Mario with a time of 1:12.762.

Mario Kart Tour
Rainbow Road reappears in Mario Kart Tour, starting with the Tokyo Tour, mostly taking on the appearance of its Mario Kart 7 iteration. However, the ramp inside the second U-turn is absent (as in the original and GBA versions), the hole in the road is even smaller than it was before (the narrow part at the end is only one tile long, and the hole in general is 7 tiles shorter), the last two Thwomps are further apart, the red tiling on the course and banner returns (in place of the pink ones in Mario Kart 7), the track edges are rounded, the track itself is thicker, and the arrow signs and Thwomp designs from the Mario Kart 8 rendition return. This course is a favorite of Rosalina, Metal Mario, Ice Mario, Pauline (Party Time), and Peach (Wedding). It is also a favorite of Dry Bones (Gold) if he is at level 3 and Peach (Kimono) if she is at level 6.

The course's R variant now includes a Glide Ramp going over a large gap, with star-shaped sets of coins appearing. The T variant includes a larger quantity of ramps, as well as steeper inclines in certain sections, while also removing all Star Thwomps; the sections that had them originally now constantly wave. The R/T variant greatly changes the layout, adding steeper inclines, sections which constantly wave (though Star Thwomps do appear unlike in the T variant), a Glide Ramp, a large amount of Star Rings, and a Mushroom Trampoline.

The course also reuses the Mario Kart 7 arrangement of its theme, while other retro courses retain their original music.

This version of Rainbow Road received two remixed versions, titled RMX Rainbow Road 1 and RMX Rainbow Road 2, first appearing in the Super Mario Kart Tour and New Year's 2021 Tour, respectively.

If the beta test is counted, Rainbow Road has appeared in more Coin Rushes than any other course, with three in total.

For a list of this course and its variants' appearances in tours, see List of SNES Rainbow Road tour appearances in Mario Kart Tour.

Trivia

 * Super Mario Kart composer Soyo Oka considers this course's theme to be one of her favorite compositions.
 * SNES Rainbow Road is the only course in Mario Kart 7 not to have a Dash Panel/ramp, and one of four courses not to have a Glide Ramp; the others are N64 Luigi Raceway,  GCN Daisy Cruiser, and Rosalina's Ice World.
 * Also, in Mario Kart 8, it is one of the two only courses that do not have any Dash Panels, Glide Ramps, underwater sections, or anti-gravity sections, with the other being GCN Yoshi Circuit, another course from DLC Pack 1.
 * In Mario Kart 8, SNES Rainbow Road, N64 Rainbow Road, the new Rainbow Road and  GCN Baby Park are the only courses in the game to have the map in different colors instead of just blue.
 * The track's location has alternated between each of its appearances. In Super Mario Kart, Mario Kart 7, and Mario Kart Tour, it is in space, but in Mario Kart: Super Circuit and Mario Kart 8, it is in the night sky.
 * Part of the music for Rainbow Road in Super Mario Kart has been referenced in the theme for Rainbow Road in Mario Kart: Super Circuit.