If you have the means, you and five of your friends can explore the seas with the U-Boat Worx C-Explorer 5.
This submersible water vehicle can dive down 200 meters and move underwater at the speed of 2.5 knots. It features a 360-degree acrylic pressure hull so you can see all around you. It features two independent life support systems, a ballast tanks system, and surface and underwater communication abilities. This U-Boat Worx C-Explorer 5 also keeps your comfort in mind with air conditioning.
The actual cost of the U-Boat Worx C-Explorer 5 is only available upon request. At one point, one popped up on an online retailer for $2.7 million. Customization options are also available, like the ability to make your sub dive 100 meters deeper.