INCREDIBLE plans for a futuristic yacht have changed the game for luxury travel as it promises to take its guests completely underwater.

The Migaloo M5 is said to be the world’s first submersible superyacht which boasts its own onboard spa and helipad and an outdoor cinema.

Appropriate for both tropical and polar environments, the vessel is made to be completely submerged for about four weeks at a depth of 820 feet.

For comparison, the British Royal Navy’s leading submarine, HMS Astute, seems a toddler at only 318ft.

This sailor’s paradise yacht is predicted to have a speed of 12 knots underwater and a range of more than 8,000 nautical miles when surfaced.

The inside of the Migaloo M5 is 1,000 square meters, of which 220 are private quarters devoted to the owner.

The 500ft vessel is designed to comfortably house up to 20 passengers and a crew of 40 as they venture into the deep sea.

A 200-square-meter spa, an outdoor theatre, a helipad, a helicopter hangar, and two “Midget Submarines” for additional deep-sea research are among the lavish amenities onboard.

A luxury interior features a 36-seat dining room with glass walls that allows guests to be fully submerged in the underwater world as they eat.

The super boat also includes two expedition vehicles, a 12.5-meter limousine tender, and a large assortment of water toys for both surface and land cruise.

The founder and CEO of Migaloo, Christian Gumpold revealed that these superyacht submarines could cost an owner upwards of $2billion.

“We think a private submarine will be the most exclusive and most expensive thing a person can own,” he previously told The Sun.

“We are the only company worldwide which offer superyacht-sized private submarines.”

He said superyacht owners are increasingly “getting younger” and “they want even more extra ordinary and individual designs”.

“They are willing to have something really new and unique, which has never been designed or constructed before – a ‘normal’ surface yacht is not that interesting for them – a private submarine is.

“We have a very deep knowledge of the yachting industry and understanding of ultra high net worth individuals as well as billionaires.

“We strongly notice trends and in our opinion submersible superyachts are the future of yachting.”

Gumpold said the private submarine adds a whole new dimension to exploring the sea, Boat International reports.

He said: “In addition to motor yachts and sailing yachts, I believe that submersible superyachts will become an additional category of private vessels that owners can choose from.”

A spokesperson for the company explained that the owner can also pick its own shipyard and other key partners for their boat.

But the Migaloo PSY team can “supervise all partners during engineering, building, sea trials and outfitting, up to handover to the owner [and] including after sales services and yacht management,” they explained.

The organisation can also oversee the development of particular knowledge training for crew members and captains.

Meanwhile, the world’s most expensive superyacht is a £4billion floating masterpiece with gold-plated sides and walls made of T-Rex bones.

Although the flashy floater is supposedly a jaw-dropping sight it remains shrouded in mystery as no one has ever actually seen it.

Dubbed History Supreme the vessel is covered in 100,000kg of gold and dazzles with jewels – but most don’t even believe it exists.

The railings, decking, dining area and even the base of the boat is all wrapped in gold and even the anchor was specially made to be dipped in liquid gold.

It was commissioned by a mysterious Malaysian billionaire and designed by artist Stuart Hughes.

It comes after the Ritz-Carlton Yacht Collection gave an exciting glimpse into the new superyacht named Ilma, which includes an onboard spa and gym, in vision on social media.

Pictures of the luxury boat shows cabins that await guests, with decor resembling a five-star hotel room leading to private terraces looking over the sea.

It also boats a huge deck for guests to bask on sunbeds.

A swimming pool with a bar behind it adds to the opulence, with separate massive dining areas.

Interior Design Director Taylor Cuff said it was in line with Ritz-Carlton’s mission to give guests “uncompromised luxury”.

And if you want a taste of the lush life, high-end flats will be up for grabs this year on the “floating millionaires row” yacht Somnio.

The invite-only luxury superyacht is lined with 39 apartments where rooms start from £8.1 million.