Marine Tube

The Marine Tube (Japanese: マリンチューブ Marine Tube) is an underwater location in Unova introduced in. It is a tube that connects Undella Town with Humilau City underneath Undella Bay.

Description
Known as "the walk-through aquarium", the Marine Tube was built during the two years between and their sequels. It was constructed to commemorate the friendship between Undella Town and Humilau City and was designed, as stated by an NPC, "to see, not to move." When the player first arrives in Undella Town, the Marine Tube is closed for cleaning and yet to open. The cleaning is completed at the same time the player earns the and defeats Team Plasma in Opelucid City.

The Marine Tube is a transparent tube made of 9.8 inch glass built to withstand high water pressures and contact with huge Pokémon. The tunnel was made above ground and lowered into the water. Crossing a six-mile-deep ocean trench, the Marine Tube is one of the many pinnacles of technology in the Unova region.

Plating corals and pyramid-like rocks can be seen in the water surrounding the tube. Lights have been placed outside the tube to provide visibility. There is a canyon halfway along the tube's route, the bottom of which cannot be seen. The Pokémon, , , , and  can be observed outside, represented with animations exclusive to this purpose. Each of these Pokémon will only appear at certain times of the day; the player can get the Wailord Watcher Medal by spotting an elusive, which are common between 3:00 PM and 5:00 PM (going by the time the player entered the Marine Tube).

There are no wild Pokémon or Trainers to battle in the Marine Tube. There are no items lying around, although the self-proclaimed first fan of Roxie will give the player a Black Sludge if they show her a Pokémon holding a Poison Barb.

If the player has given a man in an orange shirt a Fresh Water at Skyarrow Bridge, Driftveil Drawbridge, Tubeline Bridge, Village Bridge, and Marvelous Bridge, then they will meet up with the same man here. Should the player give him another Fresh Water, then he will become rehydrated and dash back to the Skyarrow Bridge with some gifts for the player.

In the Pokémon Adventures manga
The Marine Tube first appeared in PS541. and his students were taken there by Marlon and Benga after being rescued from Castelia City, which had been frozen by the Plasma Frigate.

In the TCG
This listing is of cards mentioning or featuring the Marine Tube in the Pokémon Trading Card Game.

In other languages
Unterseetunnel Acuatúnel Aquatube Tunnel Marino マリンチューブ 海洋隧道