Under the Bridge is first encountered in Big Band's story mode, and can be unlocked for multiplayer and training use by completing his story. Alternatively, owning both Big Band and the character color bundle DLC will instantly unlock Under the Bridge.
Under the Bridge shows a side of New Meridian less vivid and colorful than its bustling center. Replacing the bright lights and neon signs are construction sites and factories, sewer maintenance tunnels, and a sizable barge floating in the river under the girder bridges.
There are three different variants of Under the Bridge: One variant has no NPCs, another variant contains an assortment of vagabonds from across New Meridian, and the final variant houses many of the major staff of Lab 8, who entered the area through the sewer maintenance tunnel which is only open on this variant of the stage.
- Under the Bridge was teased several months before its official unveiling through a promotional image made for Skullgirls' Team Fortress 2 hat cross-promotion. This very early version of the stage lacked many details found in the final version, and has a slightly different design: in this unfinished iteration the floor lacks grass and puddles, a building is found where the barge normally is, a camper van is in the place of the Salt Co. truck, and a high-rise building is in the place of the construction site. Additionally, the design of the river bridges is entirely different, and the one which is fought under is seen at a different angle.
- Lulu, the dog NPC, is a patron saint NPC from the Keep Skullgirls Growing! campaign. She was chosen to appear in this stage over others as Lab Zero thought that it was the most appropriate place for her to wear a life vest.
- The heavyset NPC with a checkered coat and glasses is a reference to Matt Foley, a popular Saturday Night Live character played by actor Chris Farley who often lamented the fact that he lived "in a van, down by the river".
- A man resembling Ryu from the Street Fighter franchise, complete with headband and karate gi, can be seen in the background occasionally. Standing besides him is a punching bag resembling Bonus-kun from Waku Waku 7. This man also appears in the Streets of New Meridian Stage.
- The Under the Bridge stage contains a food van that specializes in salty items; the first item written on the truck is "Salty Cupcakes," the original name of Lab Zero's weekly Twitch stream.