Underwater Highway
The Underwater Highway is mandatory location in OMORI.
Overview
The Underwater Highway is accessed from the Deep Well. To the east is the Last Resort, only accessible via free taxis. To the west is a toll road leading to Deeper Well.
Story
Two Days Left
The Underwater Highway is only accessible on Two Days Left after Sunny overcomes his fear of drowning. In the True Route, Mari leads Omori to the Deep Well, to the north of the stump. In the Hikikomori Route, Kel leads Sunny to the Deep Well and then to the Last Resort. The toll road is inaccessible before Aubrey and Hero rejoin the party, due to it being a "double carpool" road and needing four friends to traverse it. After Mr. Jawsum and Pluto (Expanded) are defeated, the toll road is accessible. The Gator Guys give a discount to Hero, and there is a construction area Omori can use to avoid some tolls. Snaley can be fought in the construction area three times.
Notable Areas
Endless Highway
Heading east at Deep Well without taking a taxi leads to the Endless Highway. It continues infinitely in both directions, only escapable via taxis.
Toll Road
Heading west at Deep Well leads to the toll road, only accessible with Kel, Aubrey, and Hero in the party. Near the beginning of the area is a Pluto's Spaceline, a floating mirror, and a telescope, as well as the S key. Entering the first time will result in an encounter with Sweetheart, who states that she is going to visit the Sea Witches.
Mustard Sub
Mustard Sub is located on the toll road and is owned by six mermaid sisters. Captain Spaceman is singing on the stage.
Seacow Farms
Seacow Farms is southwest of Mustard Sub and home to a sidequest in which at least one squizzard must be defeated for clams. This is repeatable.