This is Warp Diving. The attraction is set inside a Saurian underwater base, where one of the Warp Portals used for interplanetary travel is located. In Warp Diving, the Saurians invite visitors to explore the Rift Dimension firsthand, aboard one of their exploratory bathyspheres.
NOTE: Knowing the lore of the Red Eye Corporation from my previous documents, you can probably guess that — in order to save money and run easy experiments on visitors — the corporation uses actual portals into the void between worlds for this attraction.
In-game, the attraction is called Buoyancy, and it comes with the “Vintage Funfair Ride Pack”. At the time of release, I got the game with that pack, preordering it to get the three additional attractions included in the preorder bonus. I haven’t preordered games in a long time — I usually wait for discounts — but Planet Coaster is a game I truly love, and I wanted the full experience.
The attraction itself… is pretty strange. It falls under the “Towers” category and is literally a metal bathysphere that gets lowered into a giant water basin. It has an oxygen tube attached at the back, and it’s submerged for a few seconds before resurfacing. This ride has only two actions in its sequence list: “Smooth surfacing” and “Burst out of the water with a jump and bounce” For my setup, I programmed the sequence to use the first option twice and the second one once.
I tried to find its real-world inspiration, and I did: it’s called the Diving Bell. Just search “Diving Bell Ride” on Google.